Methods of manufacturing and operating die-to-die inductive communication devices

ABSTRACT

Embodiments of inductive communication devices include first and second IC die and an inductive coupling substrate. The first IC die has a first coil. The inductive coupling substrate has a second coil and a first signal communication interface (e.g., a third coil or a contact). The second IC die has a second signal communication interface (e.g., a fourth coil or a contact). The first IC die and the inductive coupling substrate are arranged so that the first and second coils are aligned across a gap between the first IC die and the inductive coupling substrate. A dielectric component is positioned within the gap between the first and second coils to galvanically isolate the first IC die and the inductive coupling substrate. During operation, signals are conveyed between the first and second IC die through inductive coupling between the coils and communication through the signal communication interfaces.

RELATED APPLICATION

This patent application is a divisional of co-pending, U.S. patentapplication Ser. No. 14/104,355, filed on Dec. 12, 2013, and issued asU.S. Pat. No. 9,100,063.

TECHNICAL FIELD

Embodiments relate generally to inductive communication circuits,systems, and methods.

BACKGROUND

In a variety of applications, electrical (or galvanic) isolation isdesired between distinct circuits while enabling communication betweenthose circuits. “Galvanic isolation” means that there is no metallic orhighly conductive path between the distinct circuits. For example,galvanic isolation may be desired to protect a first circuit thatoperates at a relatively low supply voltage from a second circuit thatoperates at a relatively high supply voltage difference from the firstcircuit. In addition, galvanic isolation may be desired to isolate afirst circuit tied to a first voltage reference (e.g., ground) from asecond circuit tied to a different voltage reference (e.g., a floatingvoltage reference). Galvanic isolation also may be desired to preventextraneous transient signals produced by one circuit from being conveyedto and processed by another circuit as valid signals or data.

A specific application that may benefit from galvanic isolation may befound within an automotive hybrid electric vehicle (HEV) system, forexample. In an HEV system, a circuit that includes an insulated gatebipolar transistor (IGBT) array and corresponding gate drivers (referredto as an “IGBT circuit”) may be used to rectify AC power, and to providethe resulting DC power to a high voltage battery (e.g., 300 volts (V) ormore). A grounded control circuit (e.g., including a microcontroller)operating at a significantly lower vehicle chassis voltage (e.g., 12 V)may be used to provide control signals to the gate drivers. In order toisolate the control circuit from switching noise from the IGBT circuit,it may be desirable to provide complete galvanic isolation between thecontrol circuit and the IGBT circuit.

In other systems, for safety reasons, it may be desirable to isolateequipment that is connected to an AC power line from conductive portionsof the equipment that users can touch. In such systems, an isolationcircuit may be used to mitigate the likelihood of shocks, burns, and/orelectrocution from current flowing through a human body to ground.

Conventional techniques for providing electrical isolation include theuse of optical isolators, capacitive isolators, transformer-basedisolators, and so on. However, these techniques may be non-optimal orunsuitable for some applications, in that they may be expensive, requirea large amount of space, consume significant power, and/or have someother characteristics that may reduce their desirability for a givenapplication.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified, circuit diagram illustrating a system thatincludes an inductive communication device that provides galvanicisolation between first and second circuits, according to an exampleembodiment;

FIG. 2 is a simplified, circuit diagram illustrating a system thatincludes an inductive communication device, according to another exampleembodiment;

FIG. 3 is a cross-sectional, side view of an inductive communicationdevice, according to an example embodiment;

FIG. 4 is a cross-sectional, side view of an inductive communicationdevice, according to another example embodiment;

FIG. 5 is a cross-sectional, side view of an inductive communicationdevice, according to yet another example embodiment;

FIG. 6 is a cross-sectional, side view of an integrated circuit die thatmay be used in an inductive communication device, according to anexample embodiment;

FIG. 7 is a cross-sectional, side view of an inductive couplingsubstrate that may be used in an inductive communication device,according to an example embodiment;

FIG. 8 is a cross-sectional, side view of another integrated circuit diethat may be used in an inductive communication device, according toanother example embodiment;

FIG. 9 is a cross-sectional, side view of another inductive couplingsubstrate that may be used in an inductive communication device,according to another example embodiment;

FIG. 10 is a top view of a portion of an inductive communication device,according to an example embodiment;

FIG. 11 is a top view of a portion of an inductive communication device,according to another example embodiment;

FIG. 12 is a top view of a portion of an inductive communication device,according to yet another example embodiment;

FIG. 13 is a top view of a portion of an inductive communication device,according to yet another example embodiment;

FIG. 14 is a top view of a portion of an inductive communication device,according to yet another example embodiment;

FIG. 15 is a top view of a portion of an inductive communication device,according to yet another example embodiment; and

FIG. 16 is a flowchart of a method for manufacturing an inductivecommunication device, according to an example embodiment.

DETAILED DESCRIPTION

As will be described in more detail below, embodiments described hereininclude inductive communication devices that may be incorporated intosystems in which galvanic isolation between circuits is desired. As willbe described in more detail later, embodiments of inductivecommunication devices include at least three IC die (or two IC die andnon-IC inductive coupling substrate), and at least two of the IC dieinclude a conductive coil. Corresponding coils within the multiple dieare aligned with each other across a gap. One or more dielectriccomponents (including a physical dielectric structure) may be positionedwithin the gap, where the dielectric component(s) have properties thatprovide a desired level of galvanic isolation between the coils. Bondpads on the top surfaces of at least two of the IC die are electricallycoupled (e.g., using wirebonds) to package leads. According to anembodiment, at least two of the IC die also may include communicationcircuitry (e.g., transmitter, receiver, and/or transceiver circuitry),where the communication circuitry converts input signals intocommunication signals that are conducive to inductive communication, andafter the communication signals have been inductively communicated,converts the communication signals into an approximation of the inputsignals. According to an embodiment, the multiple IC die and theintervening dielectric component(s) all are packaged within a singleintegrated circuit package.

FIG. 1 is a simplified, circuit diagram illustrating a system 100 thatincludes an inductive communication device 130 that provides galvanicisolation between first and second circuits 110, 120, according to anexample embodiment. Accordingly, inductive communication device 130alternatively may be referred to as a “galvanic isolation device.” Insystem 100, the first circuit 110 may operate at a relatively low supplyvoltage, and the second circuit 120 may operate at a voltage differencefrom circuit 110, although circuits 110, 120 may operate without avoltage difference, as well. In addition or alternatively, the firstcircuit 110 may be tied to a first voltage reference point (e.g.,ground) and the second circuit 120 may be tied to a different voltagereference point (e.g., a floating voltage level), although circuits 110,120 may be tied to the same voltage reference point, as well. System 100may, for example, form a portion of a battery charging system for an HEV(e.g., the first circuit 110 may include a control circuit, and thesecond circuit 120 may include an array of IGBTs and associated gatedrivers), a portion of an AC power isolation system, or may form aportion of another type of system in which galvanic isolation betweenfirst and second circuits is desired.

The various components of inductive communication device 130 arepackaged in a single package (e.g., an air-cavity package or overmoldedpackage), in an embodiment. These components include a first integratedcircuit (IC) die 140, a second IC die 150, an inductive couplingsubstrate 160, and one or more dielectric components (includingdielectric structure 170) positioned between the first and second IC die140, 150 and the inductive coupling substrate 160. As used herein, a“dielectric component” may be an air gap or a physical structure thatincludes dielectric material (e.g., a layer of dielectric material oranother type of structure that includes dielectric material). As will bebetter illustrated in the Figures that follow, the first and second ICdie 140, 150 and the inductive coupling substrate 160 are physicallyarranged with respect to each other to provide inductive communicationbetween the first IC die 140 and the inductive coupling substrate 160across a gap 180, and also to provide further inductive communicationbetween the inductive coupling substrate 160 and the second IC die 150across the gap 180. The dielectric structure 170 is positioned withinthe gap 180. In some embodiments, the dielectric structure 170 maysubstantially fill the gap 180 between the surfaces of the first andsecond IC die 140, 150 and the inductive coupling substrate 160. Inother embodiments, one or more air gaps may be present within the gap180 (i.e., the gap 180 may not be completely filled by the dielectricstructure 170).

Each of the first and second IC die 140, 150 includes communicationcircuitry 142, 152 electrically coupled with a coil 144, 154. Forexample, the communication circuitry 142, 152 may include transmittercircuitry, receiver circuitry, or transceiver circuitry, in variousembodiments. According to an embodiment, each instance of thecommunication circuitry 142, 152 is formed on a same substrate (orwithin the same IC) as the coil 144, 154 to which it is connected. Inother embodiments, the communication circuitry 142, 152 may be formed ona separate IC from its associated coil 144, 154. In such embodiments,the IC that includes the coil 144, 154 and the IC that includes thecorresponding communication circuitry 142, 152 may both be includedwithin a single packaged device, or may be in distinctly packageddevices.

The inductive coupling substrate 160 includes two electrically connectedcoils 164, 166, in an embodiment. The inductive coupling substrate 160may be formed on a semiconductor substrate, in an embodiment.Alternatively, the inductive coupling substrate 160 may be formed usinga non-semiconductor substrate (e.g., a substrate formed from printedcircuit board (PCB) materials). The first and second IC die 140, 150and/or the inductive coupling substrate 160 also may include tuningcapacitors (not illustrated) configured to enhance the resonance betweenprimary/secondary coil pairs (e.g., between coil pair 144, 164 and coilpair 154, 166).

In an embodiment in which the communication circuitry 142, 152 includestransceiver circuitry, the inductive communication device 130 mayprovide bi-directional communication between the circuits 110, 120. Morespecifically, communication of a signal between the first circuit 110and the second circuit 120 may be conducted by sending a signal from thefirst circuit 110 to the first transceiver circuitry 142 via node 132,then further communicating the signal electrically from the firsttransceiver circuitry 142 to coil 144. The signal may then beinductively communicated from the coil 144 to a corresponding coil 164within the inductive coupling substrate 160. The signal then may beelectrically communicated from coil 164 to coil 166 within the inductivecoupling substrate 160. Continuing on, the signal then may beinductively communicated from coil 166 to coil 154 within the second ICdie 150, and then electrically communicated from coil 154 to transceivercircuitry 152. Finally, the signal may be electrically communicated fromtransceiver circuitry 152 to the second circuit 120 via node 136.Communication between the second circuit 120 and the first circuit 110may be similarly conducted, although in a reverse direction. In anembodiment in which communication circuitry 142 includes onlytransmitter circuitry and communication circuitry 152 includes onlyreceiver circuitry, the inductive communication device 130 supports onlyone-way communication from first circuit 110 to the second circuit 120.Conversely, in an embodiment in which communication circuitry 142includes only receiver circuitry and communication circuitry 152includes only transmitter circuitry, the inductive communication device130 supports only one-way communication from second circuit 120 to thefirst circuit 110.

Operation of inductive communication device 130 will now be described inmore detail. For ease of description, the operation will be described inconjunction with communicating a signal from first circuit 110 throughthe inductive communication device 130 to the second circuit 120. Thoseof skill in the art would understand, based on the description herein,that a signal similarly could be conducted from the second circuit 120through the inductive communication device 130 to the first circuit 110.

In order to communicate a signal from the first circuit 110 to thesecond circuit 120, the communication circuitry 142 first receives aninput signal via node 132 from the first circuit 110. The communicationcircuitry 142 then converts the input signal into a form that isappropriate for inductive communication by coil 144, which will befunctioning as a primary coil. More specifically, in an embodiment, thecommunication circuitry 142 may provide a time-varying (e.g.,oscillating) drive signal (e.g., an alternating current in the form of asinusoidal wave, a square wave, or another wave pattern) to coil 144.Coil 144 converts the drive signal into a time-varying magnetic field orflux around the coil 144. The time-varying magnetic field or fluxgenerated by coil 144 extends across the gap 180 through the dielectricstructure 170 (and other dielectric components, if they are presentwithin the gap 180) and couples with a corresponding coil 164 within theinductive coupling substrate 160. A time-varying magnetic field or fluxoriginating from a primary coil (e.g., coil 144), extending across a gap(e.g., gap 180), and received by a secondary coil (e.g., coil 164) maybe referred to herein as an “inductive communication signal.” Asdescribed above, an inductive communication signal is transmitted from aprimary coil (e.g., coil 144) to a secondary coil (e.g., coil 164)through magnetic inductive coupling between the primary/secondary coilpair. In response to the inductive communication signal coupling withcoil 164, coil 164 produces an alternating waveform or voltage, which iselectrically conveyed to coil 166 of the inductive coupling substrate160. Similar to the manner in which coils 144 and 164 communicated, thealternating waveform or voltage received by coil 166 is converted, bycoil 166, into a time-varying magnetic field or flux around coil 166.The time-varying magnetic field or flux generated by coil 166 extendsacross the gap 180 through the dielectric structure 170 (and otherdielectric components, if they are present within the gap 180) andcouples with a corresponding coil 154 within the second IC die 150. Inother words, coil 166 functions in the capacity of a primary coil, coil154 functions in the capacity of a secondary coil, and an inductivecommunication signal is conveyed between coil 166 and 154. Coil 154converts the inductive communication signal into a time-varying signal,which is received by communication circuitry 152. Communicationcircuitry 152 then converts the signal received from coil 154 into areconstructed version of the input signal (i.e., the signal received atnode 132), and provides the reconstructed version of the input signal tothe second circuit 120 via node 136.

According to an embodiment, when capable of functioning as atransmitter, communication circuitry 142, 152 includes an oscillator(not illustrated) and a driver circuit (not illustrated) configured toprovide a time-varying drive signal to the coil 144, 154 to which thecommunication circuitry 142, 152 is coupled. For example, the drivercircuit may receive an input signal (e.g., from first circuit 110 orsecond circuit 120), and may convert the input signal into analternating signal having characteristics that are conducive toinductive communication between a primary/secondary coil pair.

According to an embodiment, for example, input signal may be aninformation carrying square wave, and the driver circuit may implementamplitude-shift keying (ASK) modulation to represent the digital dataconveyed in the input signal. More specifically, for example, the drivercircuit may implement on-off keying (OOK), in which the driver circuitproduces a carrier wave at a frequency established by the oscillatorwhen the input signal has a relatively high logic level (e.g.,indicating a binary one). Conversely, the driver circuit refrains fromproducing the carrier wave when the input signal has a relatively lowlogic level (e.g., indicating a binary zero). In alternate embodiments,the driver circuit may implement other modulation techniques (e.g.,frequency modulation, phase modulation or other techniques). Accordingto an embodiment, the carrier wave conveyed within the drive signal mayhave a frequency in a band extending between about 200 megahertz (MHz)and about 400 MHz (e.g., at a frequency of about 300 MHz), although thecarrier wave may have higher or lower frequencies in other bands, aswell.

According to a further embodiment, when capable of functioning as atransmitter, communication circuitry 142, 152 includes an amplifier, adetector (not illustrated) and other circuitry configured to convert thetime-varying communication signal received from the coil 144, 154 towhich it is coupled into a reconstructed version of the signal that wasoriginally provided to the inductive communication device 130 (e.g., bythe first or second circuit 110, 120).

The dielectric structure 170 (and other dielectric components, ifpresent in the gap 180) is positioned between each primary/secondarycoil pair (i.e., between coils 144, 164 and between coils 154, 166).Although a single dielectric structure 170 is illustrated in FIG. 1,distinct dielectric structures may be used, in other embodiments (e.g.,one dielectric structure for each primary/secondary coil pair), or thedielectric structure 170 may be composed of distinct layers withdifferent dielectric properties. In addition, as mentioned previously,other dielectric components may be present within the gap 180.

The dielectric structure 170 (and other dielectric components, ifpresent within the gap 180) provides DC isolation (galvanic isolation)between the first and second IC die 140, 150 and the inductive couplingsubstrate 160, and thus between the first circuit 110 and the secondcircuit 120. The level of DC isolation provided is affected by thecombined thickness of the dielectric structure 170 and any otherdielectric components within the gap 180 (or the width of the gap 180that is established by the dielectric structure 170 and other dielectriccomponents, if present) and the dielectric constant(s) of the dielectricstructure 170 and any other dielectric components within the gap 180.For example, the dielectric structure 170 and other dielectriccomponents, if present, may be configured to provide DC isolation in arange of about 1.0 kilovolts (kV) to about 4.0 kV, or more desirablyfrom about 2.0 kV to about 5.0 kV, although dielectric structure 170 andother dielectric components, if present, may be configured to providemore or less DC isolation, as well.

FIG. 2 is a simplified, circuit diagram illustrating a system 200 thatincludes an inductive communication device 230 (or galvanic isolationdevice), according to another example embodiment. System 200 is similarto system 100 of FIG. 1, in that system 200 includes first and secondcircuits 210, 220 electrically coupled to an inductive communicationdevice 230 via nodes 232, 236. In addition, inductive communicationdevice 230 includes a first IC die 240, an inductive coupling substrate260, a second IC die 250, and one or more dielectric components(including dielectric structure 270), all of which may be packaged in asingle package, in an embodiment. A substantial difference betweeninductive communication device 230 and inductive communication device130 is that, in inductive communication device 230 the inductivecoupling substrate 260 and the second IC die 250 are communicativelycoupled through direct electrical connections, rather than through aninductive communication link.

The first and second IC die 240, 250 and the inductive couplingsubstrate 260 are physically arranged with respect to each other toprovide inductive communication between the first IC die 240 and theinductive coupling substrate 260 across a gap 280, and also to providedirect electrical communication between the inductive coupling substrate260 and the second IC die 250. Dielectric structure 270 is positionedbetween the first IC die 240 and the inductive coupling substrate 260,or more particularly in the gap 280 between coils 244, 264 of the firstIC die 240 and the inductive coupling substrate 260, respectively. Insome embodiments, the dielectric structure 270 may substantially fillthe gap 280 between the surfaces of the first IC die 240 and theinductive coupling substrate 260. In other embodiments, one or more airgaps may be present within the gap 280 (i.e., the gap 280 may not becompletely filled by the dielectric structure 270). The dielectricstructure 270 (and other dielectric components, if present within thegap 280) provides DC isolation (galvanic isolation) between the first ICdie 240 and the inductive coupling substrate 260, and thus between thefirst IC die 240 and the second IC die 250, or between the first circuit210 and the second circuit 220.

First IC die 240 is substantially the same as first IC die 240, in thatfirst IC die 240 includes communication circuitry 242 (e.g., transmittercircuitry, receiver circuitry, or transceiver circuitry) coupled to acoil 244. Second IC die 250 also includes communication circuitry 252,although communication circuitry 252 is electrically coupled withelectrical contacts 256, 258, rather than being coupled with a coil.According to an embodiment, communication circuitry 242 is formed on asame substrate (or within the same IC) as the coil 244, andcommunication circuitry 252 is formed on a same substrate (or within thesame IC) as the contacts 256, 258.

The inductive coupling substrate 260 includes coil 264 electricallycoupled with contacts 266, 268, in an embodiment. Contacts 266, 268 ofthe inductive coupling substrate 260 are electrically coupled withcontacts 256, 258 of the second IC die 250, so as to enable directelectrical communication between the inductive coupling substrate 260and the second IC die 250. The inductive coupling substrate 260 may beformed on a semiconductor substrate, in an embodiment. Alternatively,the inductive coupling substrate 260 may be formed using anon-semiconductor substrate (e.g., a substrate formed from PCBmaterials). The first IC die 240, second IC die 250, and/or theinductive coupling substrate 260 also may include tuning capacitors (notillustrated) configured to enhance the resonance between coils 244, 264.

In an embodiment in which the communication circuitry 242, 252 includestransceiver circuitry, the inductive communication device 230 mayprovide bi-directional communication between the circuits 210, 220. Morespecifically, communication of a signal between the first circuit 210and the second circuit 220 may be conducted by sending a signal from thefirst circuit 210 to the first transceiver circuitry 242 via node 232,then further communicating the signal electrically from the firsttransceiver circuitry 242 to coil 244. The signal may then beinductively communicated from the coil 244 to a corresponding coil 264within the inductive coupling substrate 260. The signal then may beelectrically communicated from coil 264 to contacts 266, 268 of theinductive coupling substrate 260. Continuing on, the signal then may beelectrically communicated from contacts 266, 268 to contacts 256, 258 ofthe second IC die 250, and then electrically communicated from contacts256, 258 to transceiver circuitry 252. Finally, the signal may beelectrically communicated from transceiver circuitry 252 to the secondcircuit 220 via node 236. Communication between the second circuit 220and the first circuit 210 may be similarly conducted, although in areverse direction. As the above description indicates, either a coil ora contact may function as a signal communication interface for an IC dieor an inductive coupling substrate. Therefore, the term “signalcommunication interface” may be used to refer to either a coil or acontact.

In an embodiment in which communication circuitry 242 includes onlytransmitter circuitry and communication circuitry 252 includes onlyreceiver circuitry, the inductive communication device 230 supports onlyone-way communication from first circuit 210 to the second circuit 220.Conversely, in an embodiment in which communication circuitry 242includes only receiver circuitry and communication circuitry 252includes only transmitter circuitry, the inductive communication device230 supports only one-way communication from second circuit 220 to thefirst circuit 210. Essentially, operation of inductive communicationdevice 230 is similar to operation of inductive communication device130, except with respect to the communication link between inductivecoupling substrate 260 and second IC die 250, which is a directelectrical communication link, rather than an inductive communicationlink.

Although inductive communication devices 130, 230 each are shown toprovide one communication path between first and second circuits 110,120, 210, 220, other embodiments of inductive communication devices mayprovide multiple communication paths (e.g., multiple forward, reverse,and/or bi-directional communication paths, such as is depicted in FIGS.12-15).

Various embodiments of an inductive communication device (e.g., device130, 230) and configurations of IC die (e.g., IC die 140, 150, 240,250), inductive coupling substrates (e.g., inductive coupling substrates160, 260), and interposed dielectric structures (e.g., dielectricstructures 170, 270) will now be described in more detail. Morespecifically, FIGS. 3 and 4 correspond to embodiments of inductivecommunication devices 300, 400 that represent physical implementationsof the circuit diagram for inductive communication device 130 (FIG. 1),and FIG. 5 corresponds to an embodiment of an inductive communicationdevice 500 that represents a physical implementation of the circuitdiagram for inductive communication device 230 (FIG. 2).

FIG. 3 is a cross-sectional, side view of an inductive communicationdevice 300 (e.g., inductive communication device 130, FIG. 1), accordingto an example embodiment. Inductive communication device 300 includes afirst IC die 310, a second IC die 320, an inductive coupling substrate330, a dielectric structure 350 positioned between the inductivecoupling substrate 330 and each of the first and second IC die 310, 320,a plurality of leads 382, 384, and a plurality of wirebonds 360, 370, inan embodiment. In addition, inductive communication device 300 mayinclude a support structure 390 and encapsulation 392. Moreparticularly, in the embodiment depicted in FIG. 3, the electricalcomponents of inductive communication device 300 of FIG. 3 are housed inan overmolded package (i.e., a package in which the electricalcomponents are substantially encased in a non-conductive (e.g., plastic)encapsulant material). As mentioned previously, embodiments of inductivecommunication devices alternatively may include electrical componentshoused in an air-cavity package (i.e., a package in which the electricalcomponents are located within an air cavity within the package, wherethe air cavity is typically sealed with a lid).

First IC die 310 includes at least one coil 312 (e.g., coil 144, FIG.1), at least one instantiation of communication circuitry 314 (e.g.,communication circuitry 142, FIG. 1), a plurality of bond pads 316, andvarious conductive traces and vias interconnecting the coil(s) 312,communication circuitry 314, and bond pads 316. In an alternateembodiment, as mentioned previously, the communication circuitry 314 maybe included in a separate die within the same package as the die thatcontains the coil(s) 312, or the communication circuitry 314 may beseparately packaged. In any of the above-described embodiment, the bondpads 316 may be considered to be electrically coupled to the coil(s) 312(e.g., either directly or indirectly through communication circuitry314). According to an embodiment, the communication circuitry 314 isformed in a semiconductor substrate, and the coil(s) 312 are formed inbuild-up layers overlying the semiconductor substrate.

Similar to first IC die 310, second IC die 320 includes at least onecoil 322 (e.g., coil 154, FIG. 1), at least one instantiation ofcommunication circuitry 324, a plurality of bond pads 326, and variousconductive traces and vias interconnecting the coil(s) 322,communication circuitry 324, and bond pads 326. As was the case with thefirst IC die 310, in an alternate embodiment, the communicationcircuitry 324 may be included in a separate die within the same packageas the die that contains the coil 322, or the communication circuitry324 may be separately packaged. In whichever embodiment, the bond pads326 may be considered to be electrically coupled to the coil 322 (e.g.,either directly or indirectly through communication circuitry 324).According to an embodiment, the communication circuitry 324 is formed ina semiconductor substrate, and the coil(s) 322 are formed in build-uplayers overlying the semiconductor substrate.

Inductive coupling substrate 330 includes first and second coils 332,334 electrically coupled together through a conductive structure 336.The conductive structure 336 may include various conductive traces andvias interconnecting the coils 332, 334, in an embodiment. Essentially,inductive coupling substrate 330 may include only passive structures, inan embodiment. In an alternate embodiment, inductive coupling structure330 may include one or more active components. For example, in analternate embodiment, inductive coupling structure 330 may include anamplifier configured to amplify a signal to be communicated betweencoils 332, 334. According to an embodiment, coils 332, 334 are formed inbuild-up layers overlying a semiconductor substrate. In an alternateembodiment, coils 332, 334 may be formed in or on a substrate comprisedof PCB materials or other materials.

According to an embodiment, each one of coils 312, 322, 332, 334 isproximate to a surface 318, 328, 338 of the IC die 310, 320 or inductivecoupling substrate 330 in which it is included. As used herein, the term“proximate to a surface,” when referring to the position of a coil,means that a portion of the coil is either exposed at the surface, orthat one or more non-conductive layers of material (e.g., dielectriclayers) is disposed over the coil, where the surface of the overlyingnon-conductive layer(s) establishes the surface of the IC or substrate.

In any event, the surfaces 318, 328, 338 of the first and second IC die310, 320 and the inductive coupling substrate 330 to which the coils313, 322, 332, 334 are proximate are arranged to face each other withindevice 300 so that a first pair of coils 312, 332 are aligned with eachother across a gap that is established by the dielectric structure 350,and a second pair of coils 322, 334 also are aligned with each otheracross the gap. The alignment of the coil pairs 312, 332 and 322, 334across the gap enables inductive communication to occur between alignedcoil pair 312 and 332, and also between aligned coil pair 322 and 334.

Dielectric structure 350 is positioned within the gap directly betweenthe coil pairs 312, 332 and 322, 334, and may extend laterally beyondthe coil pairs 312, 332 and 322, 334. According to an embodiment, athickness 352 of the dielectric structure 350 substantially equals thewidth of the gap between the coil pairs 312, 332 and 322, 334.Accordingly, the level of galvanic isolation between the coil pairs 312,332 and 322, 334 (and thus the IC die 310, 320) is directly related tothe thickness 352 of the dielectric structure 350 and the material(s)from which the dielectric structure 350 is formed. In other embodiments,other dielectric components may be present within the gap between thecoil pairs 312, 332 and 322, 334, as well. According to an embodiment,dielectric structure 350 may have a thickness 352 in a range of about 25micrometers (μm) to about 400 μm, or more desirably from about 100 μm toabout 200 μm, although dielectric structure 350 may be thinner orthicker, as well.

According to a further embodiment, the dielectric structure 350 has awidth 354, which is sufficient to allow the dielectric structure 350 toextend beyond the edges 340, 342 of the inductive coupling substrate 330by distances 356, 358. This extension of the dielectric structure 350beyond the edges 340, 342 of the inductive coupling substrate 330 mayresult in a reduction in fringing effects that may be present near theedges 340, 342.

Dielectric structure 350 may have a dielectric constant in a range ofabout 2.0 to about 5.0, although dielectric structure 350 may have alower or higher dielectric constant, as well. According to anembodiment, dielectric structure 350 includes a material selected frompolyimide, polytetrafluorethylene, benzocyclobutene, or other materialswith a suitable dielectric constant. According to a particularembodiment, dielectric structure 350 has adhesive top and/or bottomsides (e.g., dielectric structure 350 may be configured as a tape madefrom one of the aforementioned materials). Dielectric structure 350 maybe formed from a single layer of material, or dielectric structure 350may be formed from multiple layers of a single material or multiplematerials, in various embodiments.

Support structure 390 and leads 382, 384 may form portions of aleadframe, in an embodiment. In the illustrated embodiment, the supportstructure 390 and leads 382, 384 are not co-planar. Accordingly, thesupport structure 390 essentially coincides with a bottom surface ofdevice 300, and leads 382, 384 extend from the sides of device 300 atlocations that are between the bottom and top surfaces of the device300. In alternate embodiments, the support structure 390 and leads 382,384 may be co-planar. In such embodiments, the leads either may extendoutward from the bottom of the device 300, or the leads may terminate atthe sides of the device 300 (e.g., in flat no-leads types of packages).

In the embodiment illustrated in FIG. 3, the first and second IC die310, 320 are coupled to support structure 390, the dielectric structure350 is positioned on surfaces 318, 328 of the first and second IC die310, 320, and surface 338 of the inductive coupling substrate 330 iscoupled to a top surface of dielectric structure 350. Portions of thesurfaces 318, 328 of the first and second IC die 310, 320 overlap thesurface 338 of the inductive coupling substrate 330 to allow the coilpairs 312, 332 and 322, 334 to be aligned with each other. The bond pads316 of the first IC die 310 are coupled to leads 382 extending from afirst side of the device 300 via wirebonds 360. More particularly, afirst end 362 of each wirebond 360 is coupled to a bond pad 316 of firstIC die 310, and a second end 364 of each wirebond 360 is coupled to alead 382. Similarly, the bond pads 326 of the second IC die 320 arecoupled to leads 384 extending from a second side of the device 300 viawirebonds 370. More particularly, a first end 372 of each wirebond 370is coupled to a bond pad 326 of second IC die 320, and a second end 374of each wirebond 370 is coupled to a lead 384. Leads 382, 384 maycorrespond to an input node and an output node (e.g., one of leads 382,384 may correspond to one of nodes 132, 136, and the other one of leads382, 384 may correspond to the other one of nodes 132, 136, FIG. 1).

The cross-sectional view illustrated in FIG. 3 depicts a singlecommunication path between leads 382, 384. For example, the direction ofthe communication path may be from lead 382 to lead 384. In such a case,communication circuitry 314 of the first IC die 310 may be transmitteror transceiver circuitry (e.g., communication circuitry 142 FIG. 1), andthe coil 312 of the first IC die 310 may function as a primary coil.Correspondingly, communication circuitry 324 of the second IC die 320may be receiver or transceiver circuitry (e.g., communication circuitry152, FIG. 1), and the coil 322 of the second IC die 320 may function asa secondary coil. In the above-given scenario, within inductive couplingsubstrate 330, coil 332 may function as a secondary coil, and coil 334may function as a primary coil.

Alternatively, the direction of the communication path may be from lead384 to lead 382. In this case, communication circuitry 324 of the secondIC die 320 may be transmitter or transceiver circuitry, and the coil 322of the second IC die 320 may function as a primary coil.Correspondingly, communication circuitry 314 of the first IC die 310 maybe receiver or transceiver circuitry, and the coil 312 of the first ICdie 310 may function as a secondary coil. In this scenario, withininductive coupling substrate 330, coil 334 may function as a secondarycoil, and coil 332 may function as a primary coil. Although only asingle communication path is depicted in FIG. 3, inductive communicationdevice 300 also may include one or more additional communication pathsin the same direction and/or the opposite direction as the communicationpath depicted in FIG. 3.

FIG. 4 is a cross-sectional, side view of an inductive communicationdevice 400, according to another example embodiment. As mentioned above,as with inductive communication device 300 (FIG. 3) discussed above,inductive communication device 400 also represents a physicalimplementation of the circuit diagram for inductive communication device130 (FIG. 1). Inductive communication device 400 includes a number ofsimilarities to inductive communication device 300, and for the purposeof brevity, details regarding substantially similar elements andfeatures will not be repeated here.

Inductive communication device 400 includes a first IC die 410, a secondIC die 420, an inductive coupling substrate 430, a dielectric structure450 positioned between the inductive coupling substrate 430 and each ofthe first and second IC die 410, 420, a plurality of leads 482, 484, anda plurality of wirebonds 460, 470, in an embodiment. In addition, in anembodiment in which inductive communication device 400 is housed in anovermolded package, inductive communication device 400 may include asupport structure 490 and encapsulation 492. In an alternate embodiment,the electrical components of inductive communication device 400 may behoused in an air-cavity package. Inductive communication device 400provides galvanic isolation between leads 482, 484 and enables inductivecommunication through coil pairs 412, 432 and 422, 434.

Inductive communication device 400 differs from the previously-describedinductive communication device 300 in that inductive communicationdevice 400 additionally may include features that enhance the robustnessof the mechanical connection between the inductive coupling substrate430 and the first and second IC die 410, 420. More specifically,according to an embodiment, the inductive coupling substrate 430includes bond pads 454 at surface 438, which may be mechanically coupledwith correspondingly aligned bond pads 456 at the surfaces 418, 428 ofthe first and second IC die 410, 420. The aligned bond pad pairs 454,456 may be physically coupled with a coupling structure 458, such assolder, bumps, posts, or other structures. In an embodiment themechanical coupling structures (i.e., structures formed form alignedbond pads 454, 456 and a coupling structure 458) are not electricallycoupled with any circuitry of the device 400.

So as not to interfere with the coupling structures 458, inductivecommunication device 400 also may have a dielectric structure 450 with amodified shape, when compared with the embodiment of dielectricstructure 350, FIG. 3. More specifically, although the dielectricstructure 450 may (or may not) extend beyond the edges 440, 442 of theinductive coupling substrate 430 in areas where the coupling structures458 are not proximate the edges 440, 442, the dielectric structure 450may be recessed from the edges 440, 442 in areas where the couplingstructures 458 are present, as indicated in FIG. 4.

FIG. 5 is a cross-sectional, side view of an inductive communicationdevice 500, according to yet another example embodiment. As mentionedabove, inductive communication device 500 represents a physicalimplementation of the circuit diagram for inductive communication device230 (FIG. 2). Inductive communication device 500 includes a number ofsimilarities to inductive communication devices 300, 400, and for thepurpose of brevity, details regarding substantially similar elements andfeatures will not be repeated here.

Inductive communication device 500 includes a first IC die 510, a secondIC die 520, an inductive coupling substrate 530, a dielectric structure550 positioned between the inductive coupling substrate 530 and at leastthe first IC die 510, a plurality of leads 582, 584, and a plurality ofwirebonds 560, 570, in an embodiment. In addition, in an embodiment inwhich inductive communication device 500 is housed in an overmoldedpackage, inductive communication device 500 may include a supportstructure 590 and encapsulation 592. In an alternate embodiment, theelectrical components of inductive communication device 500 may behoused in an air-cavity package.

First IC die 510 is substantially the same as the previously-discussedfirst IC die 310, 410, and the first IC die 510 and the inductivecoupling substrate 530 may inductively communicate through aligned coils512, 532, as previously described. However the inductive couplingsubstrate 530 and the second IC die 520 differ from thepreviously-discussed inductive coupling substrates 330, 430 and secondIC die 320, 420, as the inductive coupling substrate 530 and the secondIC die 520 include features that enable them to communicate through anelectrical (non-inductive) interface. More specifically, althoughinductive coupling substrate 530 includes one or more first coils 532for inductively communicating with first IC die 510, inductive couplingsubstrate 530 does not include additional coils for inductivelycommunicating with second IC die 520. Instead, inductive couplingsubstrate 530 includes one or more electrical contacts 540 (e.g., bondpads) at surface 538 that are electrically coupled with the firstcoil(s) 532 (e.g., though trace(s) and/or via(s) of the inductivecoupling substrate 530). In addition, although second IC die 520 alsoincludes communication circuitry 524 and bond pads 526 (analogous tocommunication circuitry 324, 424 and bond pads 326, 426), second IC die520 does not include a coil for inductively communicating with inductivecoupling substrate 530. Instead, second IC die 520 includes one or moreelectrical contacts 542 (e.g., bond pads) at surface 528 that areelectrically coupled to the communication circuitry 524 (e.g., thoughtrace(s) and/or via(s) of the second IC die 520). The contact(s) 540 ofthe inductive coupling substrate 530 align with the contact(s) 542 ofthe second IC die 520, and the contacts 540, 542 are electricallycoupled thorough one or more electrical connections 544 (e.g., solder,bumps, conductive posts, and/or other structures).

In addition to including contacts (e.g., contacts 540, 542) that provideelectrical connections with circuitry of the first and/or second IC die510, 520 and the inductive coupling substrate 530, the first and/orsecond IC die 510, 520 and the inductive coupling substrate 530 also mayinclude mechanical coupling structures (e.g., structures formed fromaligned bond pads 554, 556 and a coupling structure 558) that are notelectrically coupled with any circuitry of the device 500.

More detailed examples of embodiments of IC die and inductive couplingsubstrates will now be described. More particularly, FIG. 6 is across-sectional, side view of an IC die 600 that includes a coil 640(e.g., IC die 140, 150, 240, 310, 320, 410, or 510, FIGS. 1-5) may beused in an inductive communication device (e.g., inductive communicationdevice 130, 230, 300, 400, 500, FIGS. 1-5), according to an exampleembodiment. IC die 600 includes a semiconductor substrate 602, and abuild-up structure 610 comprising a plurality of conductive layers 612,613, 614, 615 and dielectric layers 616, 617, 618, 619, 620 on a topsurface of the semiconductor substrate 602. For consistency with FIGS.3-5 and enhanced understanding, IC die 600 is shown in the sameorientation as IC die 310, 410, 510 of FIGS. 3-5 (i.e., with the surface604 to which coil 640 is proximate facing upward).

Various active components forming communication circuitry 630 are formedin the semiconductor substrate 602. For example, the communicationcircuitry 630 may include transmitter circuitry, receiver circuitry ortransceiver circuitry, in various embodiments. The components of thecommunication circuitry 630 are interconnected through conductive tracesformed in some or all of the conductive layers 612-615 and conductivevias formed between the conductive layers 612-615. One or more bond pads650 may be formed in an uppermost conductive layer 615, and the bondpads 650 may be electrically coupled to the communication circuitry 630with conductive vias formed through the dielectric layers 616-619 andconductive traces formed between the vias in the conductive layers612-615.

In addition, IC die 600 includes a coil 640 (e.g., one of coils 144,154, 244, 312, 322, 412, 512, FIGS. 1-3, 5), which includes multiplesubstantially-concentric conductive rings 641, 642, 643 formed in one ormore uppermost conductive layers 613-615 (i.e., formed proximate tosurface 604 of IC die 600). For example, in the embodiment illustratedin FIG. 6, coil 640 includes conductive rings formed in the uppermostthree conductive layers 613-615. The conductive rings in the variouslayers 613-615 are interconnected through conductive vias 644, 645 toform a continuous conductive coil having first and second ends that areelectrically coupled to the communication circuitry 630. For example, afirst end of the coil 640 may be coupled to the communication circuitry630 through conductive via 646 and other conductive structures (notillustrated) between the coil 640 and the communication circuitry 630,and a second end of the coil 640 may be coupled to the communicationcircuitry 630 through conductive via 647 and still other conductivestructures (not illustrated) between the coil 640 and the communicationcircuitry 630. In other embodiments, coil 640 may be formed using feweror more than three conductive layers, and/or the ends of coil 640 may belocated on a same conductive layer. In addition, vias 644, 645 showninterconnecting the concentric conductive rings 641-643 may be locatedin other positions, and/or multiple vias may be used to provide aplurality of cross-overs used to construct the continuous coil 640.

The uppermost dielectric layer 620 may or may not overlie the coil 640,in various embodiments. In an embodiment in which the uppermostdielectric layer 620 does overlie the coil 640 (e.g., the embodimentillustrated in FIG. 6), the height of the portion of the uppermostdielectric layer 620 overlying the coil 640 contributes to the thicknessof the gap (e.g., gap thickness 352, FIG. 3) between the IC die 600 andan inductive coupling substrate (e.g., inductive coupling substrate,160, 260, 330, 430, 530, FIGS. 1-5) that is positioned over the IC die600. In addition, the portion of the uppermost dielectric layer 620overlying the coil 640 may contribute to the overall level of galvanicisolation between IC 600 and the inductive coupling substrate, whenarranged according to the embodiments discussed herein.

Referring also to FIGS. 1-5, embodiments of IC die 600 may be used, forexample, for both the first and second IC die 140, 150 in FIG. 1, justthe first IC die 240 in FIG. 2, both the first and second IC die 310,320 in FIG. 3, both the first and second IC die 410, 420 in FIG. 4, orjust the first IC die 510 in FIG. 5. When IC die 600 is incorporatedinto an inductive communication device (e.g., device 130, 230, 300, 400,500, FIGS. 1-5), a wire bond (e.g., wirebond 360, 370, 460, 470, 560,FIGS. 3-5) may be coupled between the bond pad 650 and a device lead(e.g., lead 382, 384, 482, 484, 582, FIGS. 3-5). For example, bond pad650 may correspond to a bond pad configured to receive a communicationsignal from external circuitry or to provide a communication signal toexternal circuitry (e.g., to first or second circuit 110, 120, 210,FIGS. 1, 2). In addition, the coil 640 may be aligned with acorresponding coil of an overlying inductive coupling substrate (e.g.,coil 164, 166, 264, 332, 334, 432, 434, 532, FIGS. 1-5) with adielectric structure (e.g., dielectric structure 170, 270, 350, 450,550, FIGS. 1-5) positioned in the gap between the coils.

As discussed previously, in an embodiment of an inductive communicationdevice in which both IC die include a coil, such as the embodimentsdepicted in FIGS. 1, 3, and 4, the corresponding inductive couplingsubstrate (e.g., inductive coupling substrates 160, 330, 430, FIGS. 1,3, 4) includes two coils, where each of the two coils are configured tosupport inductive communication between a different one of the two coilsin the IC die. An embodiment of such an inductive coupling substratewill now be described in the context of FIG. 7.

FIG. 7 is a cross-sectional, side view of an inductive couplingsubstrate 700 (e.g., inductive coupling substrate 160, 330, 430, FIGS.1, 3, 4) that may be used in an inductive communication device (e.g.,inductive communication devices 130, 300, 400, FIGS. 1, 3, 4), accordingto an example embodiment. Referring also to FIGS. 1, 3, and 4,embodiments of inductive coupling substrate 700 may be used, forexample, as inductive coupling substrate 160, 330, and 430.

Inductive coupling substrate 700 includes a substrate 702, and abuild-up structure 710 comprising a plurality of conductive layers 711,712, 713, 714, 715 and dielectric layers 716, 717, 718, 719, 720 on atop surface of the substrate 702. For consistency with FIGS. 3 and 4 andenhanced understanding, inductive coupling substrate 700 is shown in thesame orientation as inductive coupling substrate 330, 430 of FIGS. 3, 4(i.e., with the surface 704 to which coils 740, 750 are proximate facingdownward).

Inductive coupling substrate 700 includes two coils 740, 750 (e.g.,coils 332, 334, 432, 434, FIGS. 3, 4), each of which includes multiplesubstantially-concentric conductive rings 741, 742, 743 and 751, 752,753 formed in one or more uppermost conductive layers 713-715 (i.e.,formed proximate to surface 704 of inductive coupling substrate 700).For example, in the embodiment illustrated in FIG. 7, each of coils 740,750 includes conductive rings formed in the uppermost three conductivelayers 713-715. The conductive rings in the various layers 713-715 areinterconnected through conductive vias 744, 745, 754, 755 to formcontinuous conductive coils having first and second ends that areelectrically coupled to each other through additional interconnections.For example, a first end of coil 740 may be coupled to a first end ofcoil 750 through conductive vias 746, 756 and conductive trace 762between coil 740 and coil 750, and a second end of coil 740 may becoupled to a second end of coil 750 through conductive vias 747, 757 andconductive trace 764 between coil 740 and coil 750. In otherembodiments, coils 740, 750 may be formed using fewer or more than threeconductive layers, and/or the ends of coils 740, 750 may be located on asame conductive layer. In addition, vias 744, 745, 754, 755 showninterconnecting the concentric conductive rings 741-743 and 751-753 maybe located in other positions, and/or multiple vias may be used toprovide a plurality of cross-overs used to construct the continuouscoils 740, 750. Further, the coils 740, 750 may be interconnected usingdifferent conductive structures than those depicted in FIG. 7.

The uppermost dielectric layer 720 may or may not overlie the coils 740,750, in various embodiments. In an embodiment in which the uppermostdielectric layer 720 does overlie the coils 740, 750 (e.g., theembodiment illustrated in FIG. 7), the height of the portion of theuppermost dielectric layer 720 overlying the coils 740, 750 contributesto the thickness of the gap (e.g., gap thickness 352, FIG. 3) betweenthe inductive coupling substrate 700 and an IC die (e.g., IC die 140,150, 310, 320, 410, 420, FIGS. 1, 3, 4) that is positioned under theinductive coupling substrate 700. In addition, the portion of theuppermost dielectric layer 720 overlying the coils 740, 750 maycontribute to the overall level of galvanic isolation between theinductive coupling substrate 700 and the IC die, when arranged accordingto the embodiments discussed herein.

Referring also to FIGS. 1, 3, and 4, embodiments of inductive couplingsubstrate 700 may be used, for example, for inductive couplingsubstrates 160, 330, and 430. When inductive coupling substrate 700 isincorporated into an inductive communication device (e.g., device 130,300, 400, FIGS. 1, 3, 4), coil 740 may be aligned with a correspondingcoil of an underlying first IC die (e.g., coil 144, 312, 412, of IC die140, 310, 410, FIGS. 1, 3, 4), and coil 750 may be aligned with acorresponding coil of an underlying second IC (e.g., coil 154, 322, 422,of IC die 150, 320, 420, FIGS. 1, 3, 4) with a dielectric structure(e.g., dielectric structure 170, 350, 450, FIGS. 1, 3, 4) positioned inthe gap between the coils.

As discussed in detail above in conjunction with FIGS. 2 and 5, in someembodiments of an inductive communication device, one of the IC die(e.g., IC die 250, 520, FIGS. 2, 5) does not include a coil, but insteadincludes contacts (e.g., contacts 256, 258, 542, FIGS. 2, 5) that enablethe IC die to communicate over a direct electrical connection (i.e.,non-inductively) with an inductive coupling substrate. FIGS. 8 and 9,described in detail below, correspond to embodiments of an IC die 800with contacts rather than a coil, and an inductive coupling substrate900 configured to communicate with such an IC die as well as an IC diewith a coil.

FIG. 8 is a cross-sectional, side view of an IC die 800 that includescontacts 852, 854, rather than a coil (e.g., IC die 250, 520, FIGS. 2,5) that may be used in an inductive communication device (e.g.,inductive communication device 230 or 500, FIGS. 2, 5), according to anexample embodiment. IC die 800 includes a semiconductor substrate 802,and a build-up structure 810 comprising a plurality of conductive layers812, 813 and dielectric layers 818, 819, 820 formed over a top surfaceof the semiconductor substrate 802. For consistency with FIG. 5 andenhanced understanding, IC die 800 is shown in the same orientation asIC die 520 of FIG. 5 (i.e., with the surface 804 of IC die 800 to whichcontacts 850, 852, 854 are proximate facing upward).

Various active components forming communication circuitry 830 are formedin the semiconductor substrate 802. For example, the communicationcircuitry 830 may be transmitter circuitry, receiver circuitry ortransceiver circuitry, in various embodiments. The components of thecommunication circuitry 830 are interconnected through conductive tracesformed in some or all of the conductive layers 812, 813 and conductivevias formed between the conductive layers 812, 813.

According to an embodiment, one or more bond pads 850 and one or morecontacts 852, 854 (e.g., also bond pads) may be formed in conductivelayer 813 proximate to (e.g., on) a surface 804 of the IC die 800. Thebond pads 850 and contacts 852, 854 may be electrically coupled to thecommunication circuitry 830 with conductive vias extending through thebuild-up structure 810, along with one or more conductive traces (notshown) in intervening conductive layers.

When IC die 800 is incorporated into an inductive communication device(e.g., device 230, 500, FIGS. 2, 5), a wire bond (e.g., wirebond 570,FIG. 5) may be coupled between bond pad 850 and a device lead (e.g.,lead 584, FIG. 5). For example, bond pad 850 may correspond to a bondpad configured to receive a communication signal from external circuitryor to provide a communication signal to external circuitry (e.g., secondcircuit 220, FIG. 2). In addition, contacts 852, 854 (e.g., contacts256, 258, 542, FIGS. 2, 5) may be coupled to corresponding contacts(e.g., contacts 266, 268, 540, 952, 954, FIGS. 2, 5, 9) of an inductivecoupling substrate (e.g., inductive coupling substrates 260, 530, 900,FIGS. 2, 5, 9) with electrical connections (e.g., electrical connection544, FIG. 5), thus establishing conductive paths between thecommunication circuitry 830 and a coil (e.g., coil 264, 532, FIGS. 2, 5)of the inductive coupling substrate.

FIG. 9 is a cross-sectional, side view of another inductive couplingsubstrate 900 (e.g., inductive coupling substrate 260, 530, FIGS. 2, 5)that may be used in an inductive communication device (e.g., inductivecommunication devices 230, 500, FIGS. 2, 5), according to anotherexample embodiment. Referring also to FIGS. 2 and 5, embodiments ofinductive coupling substrate 900 may be used, for example, as inductivecoupling substrate 260 and 530.

Inductive coupling substrate 900 includes a substrate 902, and abuild-up structure 910 comprising a plurality of conductive layers 911,912, 913, 914, 915 and dielectric layers 916, 917, 918, 919, 920 on atop surface of the substrate 902. For consistency with FIG. 5 andenhanced understanding, inductive coupling substrate 900 is shown in thesame orientation as inductive coupling substrate 530 of FIG. 5 (i.e.,with the surface 904 to which coil 940 is proximate facing downward).

Inductive coupling substrate 900 includes coil 940 (e.g., coil 264, 532,FIGS. 2, 5) and two contacts 952, 954 (e.g., contacts 266, 268, 540,FIGS. 2, 5). Coil 940 includes multiple substantially-concentricconductive rings 941, 942, 943 formed in one or more uppermostconductive layers 913-915 (i.e., formed proximate to surface 904 ofinductive coupling substrate 900). For example, in the embodimentillustrated in FIG. 9, coil 940 includes conductive rings formed in theuppermost three conductive layers 913-915. The conductive rings in thevarious layers 913-915 are interconnected through conductive vias 944,945 to form a continuous conductive coil having first and second endsthat are electrically coupled to contacts 952, 954.

For example, a first end of coil 940 may be coupled to a first contact952 through conductive vias 946, 947 and conductive trace 962 betweencoil 940 and contact 952, and a second end of coil 940 may be coupled toa second contact 954 through conductive vias 948, 949 and conductivetrace 964 between coil 940 and contact 954. In other embodiments, coil940 may be formed using fewer or more than three conductive layers,and/or the ends of coil 940 may be located on a same conductive layer.In addition, vias 944, 945 shown interconnecting the concentricconductive rings 941-943 may be located in other positions, and/ormultiple vias may be used to provide a plurality of cross-overs used toconstruct the continuous coil 940. Further, the coil 940 and contacts952, 954 may be interconnected using different conductive structuresthan those depicted in FIG. 9.

The uppermost dielectric layer 920 may or may not overlie the coil 940,in various embodiments. In an embodiment in which the uppermostdielectric layer 920 does overlie the coil 940 (e.g., the embodimentillustrated in FIG. 9), the height of the portion of the uppermostdielectric layer 920 overlying the coil 940 contributes to the thicknessof the gap between the inductive coupling substrate 900 and an IC diethat is positioned under the inductive coupling substrate 900 (e.g., thegap between IC die 510 and inductive coupling substrate 530, FIG. 5). Inaddition, the portion of the uppermost dielectric layer 920 overlyingthe coil 940 may contribute to the overall level of galvanic isolationbetween the inductive coupling substrate 900 and the IC die, whenarranged according to the embodiments discussed herein.

Referring also to FIGS. 2 and 5, embodiments of inductive couplingsubstrate 900 may be used, for example, for inductive couplingsubstrates 260, 530. When inductive coupling substrate 900 isincorporated into an inductive communication device (e.g., device 230,500, FIGS. 2, 5), coil 940 may be aligned with a corresponding coil ofan underlying first IC die (e.g., coil 244, 512, of IC die 240, 510,FIGS. 2, 5) with a dielectric structure (e.g., dielectric structure 270,550, FIGS. 2, 5) positioned in the gap between the coils. In addition,contacts 952, 954 (e.g., contacts 266, 268, 540, FIGS. 2, 5) may becoupled to corresponding contacts (e.g., contacts 256, 258, 542, 852,854, FIGS. 2, 5, 8) of an IC die (e.g., IC die 250, 520, 800, FIGS. 2,5, 8) with electrical connections (e.g., electrical connection 544, FIG.5), thus establishing conductive paths between the inductive couplingsubstrate 900 and the IC die.

Various embodiments of arrangements of different types of IC die andinductive coupling substrates within an inductive communication devicewill now be described in conjunction with FIGS. 10-15. Moreparticularly, FIGS. 10-15 depict embodiments of inductive communicationdevices that include a single communication path (FIGS. 10, 11),multiple parallel communication paths (FIGS. 12, 13), and a singlecommunication path in which the input signal is split into multiplepaths for inductive communication, and then recombined into a singlesignal after inductive communication (FIGS. 14, 15).

FIG. 10 is a top view of a portion of an inductive communication device1000 with a single communication path that includes a two-coil inductivecoupling substrate 1030, and thus two serially arrangedprimary/secondary coil pairs 1012, 1032 and 1022, 1034, according to anexample embodiment. More particularly, FIG. 10 illustrates the topsurface of a first IC die 1010 (partially obscured), a second IC die1020 (partially obscured), and an inductive coupling substrate 1030(overlying and partially obscuring the first and second IC die 1010,1020). A dielectric structure 1050 with a perimeter that extends beyondthe perimeter of the inductive coupling substrate 1030 is positioned ina gap (e.g., gap 180, FIG. 1) between the bottom surface of theinductive coupling substrate 1030 and the first and second IC die 1010,1020. Except for the exclusion of leads and wirebonds, the inductivecommunication device 1000 may have a cross-section (along a plane thatextends from left to right in FIG. 10) that is substantially similar tothe cross-sectional view in FIG. 3, for example. In an embodiment inwhich the width of the dielectric structure 1050 were less that thewidth of the inductive coupling substrate 1030, the inductivecommunication device 1000 may have a cross-section that is substantiallysimilar to the cross-sectional view in FIG. 4, for example.

First IC die 1010 includes a coil 1012 proximate to the top surface ofthe first IC die 1010, first communication circuitry 1014 (e.g.,transmitter, receiver, or transceiver circuitry), and a plurality offirst bond pads 1016 proximate to the top surface of the first IC die1010. Coil 1012 consists of a continuous conductive structure (i.e.,continuous between an input terminal 1018 and an output terminal 1019)that includes multiple substantially-concentric conductive rings thatmay be located in multiple conductive layers of the first IC die 1010.In FIG. 10, coil 1012 does not appear to consist of a continuousconductive structure between input terminal 1018 and output terminal1019, as there are various discontinuities shown within coil 1012. Thediscontinuities are shown to simplify the depiction of coil 1012, andalso to indicate that the coil's concentric rings may be coupled throughconductive vias to concentric rings in underlying conductive layers,further conveying that the structure of coil 1012 may be a multi-layerstructure that includes a plurality of cross-overs to establish acontinuous conductive structure. This same depiction of coils alsoapplies to the other coils 1022, 1032, 1034 in FIG. 10 and to the coilsdepicted in FIGS. 11-15.

Second IC die 1020 also includes a coil 1022 proximate to the topsurface of the second IC die 1020, second communication circuitry 1024(e.g., receiver, transmitter, or transceiver circuitry), and a pluralityof second bond pads 1026 proximate to the top surface of the second ICdie 1020. Coil 1022 also consists of a continuous conductive structurethat includes multiple substantially-concentric conductive rings thatmay be located in multiple conductive layers of the second IC die 1020.Some of first and second bond pads 1016, 1026 may be used to receivevoltage supplies (e.g., power and ground), and other ones of first andsecond bond pads 1016, 1026 may be used to receive input signals, conveyoutput signals, receive control signals, or to convey other types ofsignals. Although each set of bond pads 1016, 1026 is shown to includefour bond pads 1016, 1026, each IC 1010, 1020 may include more or fewerbond pads.

Also depicted in FIG. 10 is the top surface of inductive couplingsubstrate 1030 overlying and partially obscuring the first and second ICdie 1010, 1020. The inductive coupling substrate 1030 includes two coils1032, 1034 (not specifically apparent as the coils 1032, 1034 aresubstantially aligned with and overlie coils 1012, 1022, respectively),respective ends of which are electrically coupled together withconductive structures 1036, 1038.

Also depicted in FIG. 10 is dielectric structure 1050, which also ispartially obscured by inductive coupling substrate 1030. As discussedpreviously, when arranged to provide inductive communication betweencoils 1012, 1032 of the first IC die 1010 and the inductive couplingsubstrate 1030, and further inductive communication between theinductive coupling substrate 1030 and the second IC die 1020, thesurfaces of the first and second IC die 1010, 1020 to which the coils1012, 1022 are proximate are oriented to face the surface of inductivecoupling substrate 1030 to which coils 1032, 1034 are proximate. Inaddition, the coils 1012, 1032 are substantially aligned with eachother, and coils 1022, 1034 are substantially aligned with each otheracross a gap (e.g., gap 180, FIG. 1), where the gap is established atleast in part by the dielectric structure 1050. As shown, the dielectricstructure 1050 is arranged so that it is present across the entire areaof overlap of the coils 1012, 1032 and 1022, 1034. According to afurther embodiment, and as mentioned above, the dielectric structure1050 may have dimensions such that the dielectric structure 1050 extendsbeyond some or all of the edges of the inductive coupling substrate1030. In another embodiment, the dielectric structure 1050 may havedimensions such that the dielectric structure 1050 does not extendbeyond, but is retreated from, some or all of the edges of the inductivecoupling substrate 1030.

FIG. 11 is a top view of a portion of an inductive communication device1100, according to another example embodiment. More particularly, FIG.11 illustrates the top surface of a first IC die 1110 (partiallyobscured), a second IC die 1120 (partially obscured), and an inductivecoupling substrate 1130 (overlying and partially obscuring the first andsecond IC die 1110, 1120). A dielectric structure 1150 with a perimeterthat extends beyond the perimeter of the inductive coupling substrate1130 is positioned in a gap (e.g., gap 280, FIG. 2) between the bottomsurface of the inductive coupling substrate 1130 and at least the firstIC die 1110. Except for the exclusion of leads and wirebonds, theinductive communication device 1100 may have a cross-section (along aplane that extends from left to right in FIG. 11) that is substantiallysimilar to the cross-sectional view in FIG. 5, for example. Theinductive communication device 1100 of FIG. 11 is similar to theinductive communication device 1000 of FIG. 10, except that theinductive coupling substrate 1130 has a single coil 1132 for inductivelycommunicating with the first IC die 1110, and contacts 1140 forcommunicating with the second IC die 1120.

First IC die 1110 includes a coil 1112 proximate to the top surface ofthe first IC die 1110, first communication circuitry 1114 (e.g.,transmitter, receiver, or transceiver circuitry), and a plurality offirst bond pads 1116 proximate to the top surface of the first IC die1110. Coil 1112 consists of a continuous conductive structure thatincludes multiple substantially-concentric conductive rings that may belocated in multiple conductive layers of the first IC die 1110.

Second IC die 1120 does not include a coil, but instead includescontacts 1142 proximate to the top surface of the second IC die 1120,second communication circuitry 1124 (e.g., receiver, transmitter, ortransceiver circuitry), and a plurality of second bond pads 1126proximate to the top surface of the second IC die 1120. The contacts1126 are electrically coupled with the contacts 1140 of the inductivecoupling substrate 1130 to provide for direct electrical communicationbetween the second IC die 1120 and the inductive coupling substrate1130. Some of first and second bond pads 1116, 1126 may be used toreceive voltage supplies (e.g., power and ground), and other ones offirst and second bond pads 1116, 1126 may be used to receive inputsignals, convey output signals, receive control signals, or to conveyother types of signals. Although each set of bond pads 1116, 1126 isshown to include four bond pads 1116, 1126, each IC 1110, 1120 mayinclude more or fewer bond pads.

Also depicted in FIG. 11 is the top surface of inductive couplingsubstrate 1130 overlying and partially obscuring the first and second ICdie 1110, 1120. The inductive coupling substrate 1130 includes coil 1132(which is substantially aligned with and overlies coil 1112), andcontacts 1140, which are electrically coupled to coil 1132 withconductive structures 1136, 1138.

Also depicted in FIG. 11 is dielectric structure 1150, which also ispartially obscured by inductive coupling substrate 1130. As discussedpreviously, when arranged to provide inductive communication betweencoils 1112, 1132 of the first IC die 1110 and the inductive couplingsubstrate 1130, the surfaces of the first IC die 1110 to which the coil1112 is proximate is oriented to face the surface of inductive couplingsubstrate 1130 to which coil 1132 is proximate. In addition, the coils1112, 1132 are substantially aligned with each other across a gap (e.g.,gap 280, FIG. 2), where the gap is established at least in part by thedielectric structure 1150. As shown, the dielectric structure 1150 isarranged so that it is present across the entire area of overlap of thecoils 1112, 1132. According to a further embodiment, the dielectricstructure 1150 may have dimensions such that the dielectric structure1150 extends beyond some or all of the edges of the inductive couplingsubstrate 1130. In another embodiment, the dielectric structure 1150 mayhave dimensions such that the dielectric structure 1150 does not extendbeyond, but is retreated from, some or all of the edges of the inductivecoupling substrate 1130.

The embodiments depicted in FIGS. 10 and 11 provide for a single one-wayor bi-directional communication path between first communicationcircuitry 1014, 1114 and second communication circuitry 1024, 1124. Forexample, when first communication circuitry 1014, 1114 includestransmitter circuitry and second communication circuitry 1024, 1124includes receiver circuitry, a one-way communication path may beestablished from left to right in FIGS. 10 and 11. Conversely, whenfirst communication circuitry 1014, 1114 includes receiver circuitry andsecond communication circuitry 1024, 1124 includes transmittercircuitry, a one-way communication path may be established from right toleft in FIGS. 10 and 11. When first and second communication circuitry1014, 1114, 1024, 1124 each include transceiver circuitry, atime-duplexed, bi-directional communication path may be establishedbetween the first and second communication circuitry 1014, 1114, 1024,1124.

In various alternate embodiments, an inductive communication device mayinclude multiple parallel communication paths. For example, FIG. 12 is atop view of a portion of an inductive communication device 1200 with twocommunications paths, each of which includes a two serially-arrangedprimary/secondary coil pairs (i.e., coil pairs 1212, 1232 and 1222,1234, and coil pairs 1213, 1233 and 1227, 1237), according to anotherexample embodiment. Similar to the embodiment depicted in FIG. 10, FIG.12 illustrates the top surface of a first IC die 1210 (partiallyobscured), a second IC die 1220 (partially obscured), and an inductivecoupling substrate 1230 (overlying and partially obscuring the first andsecond IC die 1210, 1220). A dielectric structure 1250 with a perimeterthat extends beyond the perimeter of the inductive coupling substrate1230 is positioned in a gap (e.g., gap 180, FIG. 1) between the bottomsurface of the inductive coupling substrate 1230 and the first andsecond IC die 1210, 1220.

The first IC die 1210 includes a pair of spatially-separated coils 1212,1213 proximate to the top surface of the first IC die 1210, firstcommunication circuitry 1214 (e.g., transmitter, receiver, ortransceiver circuitry), second communication circuitry 1215 (e.g.,transmitter, receiver, or transceiver circuitry), and a plurality offirst bond pads 1216. The second IC die 1220 includes a pair ofspatially-separated coils 1222, 1227, third communication circuitry 1224(e.g., receiver, transmitter, or transceiver circuitry), fourthcommunication circuitry 1225 (e.g., receiver, transmitter, ortransceiver circuitry), and a second plurality of bond pads 1226. Someof first and second bond pads 1216, 1226 may be used to receive voltagesupplies (e.g., power and ground), and other ones of first and secondbond pads 1216, 1226 may be used to receive input signals, convey outputsignals, receive control signals, or to convey other types of signals.Although each set of first and second bond pads 1216, 1226 is shown toinclude eight bond pads 1216, 1216, each IC 1210, 1220 may include moreor fewer bond pads.

Also depicted in FIG. 12 is the top surface of inductive couplingsubstrate 1230 overlying and partially obscuring the first and second ICdie 1210, 1220. The inductive coupling substrate 1230 includes twospatially-separated pairs of serially-connected coils, or morespecifically serially connected coils 1232, 1234 and serially-connectedcoils 1233, 1237. The ends of each pair of serially-connected coils areelectrically coupled together with conductive structures 1238, 1239.

Also depicted in FIG. 12 is dielectric structure 1250, which also ispartially obscured by inductive coupling substrate 1230. When arrangedto provide inductive communication between coils 1212, 1232, 1213, 1233of the first IC die 1210 and the inductive coupling substrate 1230, andfurther inductive communication between coils 1222, 1234, 1227, 1237 ofthe second IC die 1220 and the inductive coupling substrate 1230, thesurfaces of the first and second IC die 1210, 1220 to which the coils1212, 1213, 1222, 1227 are proximate are oriented to face the surface ofinductive coupling substrate 1230 to which coils 1232, 1233, 1234, 1237are proximate. In addition, coils 1212, 1232 are substantially alignedwith each other, coils 1213, 1233 are substantially aligned with eachother, coils 1222, 1234 are substantially aligned with each other, andcoils 1227, 1237 are substantially aligned with each other across a gap(e.g., gap 180, FIG. 1), where the gap is established at least in partby the dielectric structure 1250. As shown, the dielectric structure1250 is arranged so that it is present across the entire area of overlapof the coils 1212, 1232, coils 1222, 1234, coils 1213, 1233, and coils1227, 1237. According to a further embodiment, and as mentioned above,the dielectric structure 1250 may have dimensions such that thedielectric structure 1250 extends beyond some or all of the edges of theinductive coupling substrate 1230. In another embodiment, the dielectricstructure 1250 may have dimensions such that the dielectric structure1250 does not extend beyond, but is retreated from, some or all of theedges of the inductive coupling substrate 1230.

FIG. 13 is a top view of a portion of an inductive communication device1300 with two communications paths, each of which includes a twoserially-arranged primary/secondary coil pairs and contacts (i.e., coilpairs 1312, 1332 and contacts 1322, 1334, and coil pairs 1313, 1333 andcontacts 1327, 1337), according to another example embodiment. Similarto the embodiment depicted in FIG. 10, FIG. 13 illustrates the topsurface of a first IC die 1310 (partially obscured), a second IC die1320 (partially obscured), and an inductive coupling substrate 1330(overlying and partially obscuring the first and second IC die 1310,1320). A dielectric structure 1350 with a perimeter that extends beyondthe perimeter of the inductive coupling substrate 1330 is positioned ina gap (e.g., gap 280, FIG. 2) between the bottom surface of theinductive coupling substrate 1330 and at least the first IC die 1310.The inductive communication device 1300 of FIG. 13 is similar to theinductive communication device 1200 of FIG. 12, except that, along eachcommunication path, the inductive coupling substrate 1330 has a singlecoil 1332, 1333 for inductively communicating with the first IC die1310, and contacts 1334, 1337 for communicating with the second IC die1320.

The first IC die 1310 includes a pair of spatially-separated coils 1312,1313 proximate to the top surface of the first IC die 1310, firstcommunication circuitry 1314 (e.g., transmitter, receiver, ortransceiver circuitry), second communication circuitry 1315 (e.g.,transmitter, receiver, or transceiver circuitry), and a plurality offirst bond pads 1316. Second IC die 1320 does not include coils, butinstead includes two sets of contacts 1322, 1327 proximate to the topsurface of the second IC die 1320, third communication circuitry 1324(e.g., receiver, transmitter, or transceiver circuitry), fourthcommunication circuitry 1325 (e.g., receiver, transmitter, ortransceiver circuitry), and a plurality of second bond pads 1326proximate to the top surface of the second IC die 1320. The contacts1322, 1327 are electrically coupled with corresponding sets of contacts1334, 1337 of the inductive coupling substrate 1330 to provide fordirect electrical communication between the second IC die 1320 and theinductive coupling substrate 1330. Some of first and second bond pads1316, 1326 may be used to receive voltage supplies (e.g., power andground), and other ones of first and second bond pads 1316, 1326 may beused to receive input signals, convey output signals, receive controlsignals, or to convey other types of signals. Although each set of bondpads 1316, 1326 is shown to include eight bond pads 1316, 1326, each IC1310, 1320 may include more or fewer bond pads.

Also depicted in FIG. 13 is the top surface of inductive couplingsubstrate 1330 overlying and partially obscuring the first and second ICdie 1310, 1320. The inductive coupling substrate 1330 includes a pair ofspatially-separated coils 1332, 1333 (which are substantially alignedwith and overlie coils 1312, 1313), and two sets of contacts 1334, 1337.The ends of each of the coils 1332, 1333 are electrically coupled withone of the sets of contacts 1334, 1337 with conductive structures 1338,1339.

Also depicted in FIG. 13 is dielectric structure 1350, which also ispartially obscured by inductive coupling substrate 1330. When arrangedto provide inductive communication between coils 1312, 1332, 1313, 1333of the first IC die 1310 and the inductive coupling substrate 1330, thesurface of at least the first IC die 1310 to which the coils 1312, 1313are proximate is oriented to face the surface of inductive couplingsubstrate 1330 to which coils 1332, 1333 are proximate. In addition,coils 1312, 1332 are substantially aligned with each other, and coils1313, 1333 are substantially aligned with each other across a gap (e.g.,gap 280, FIG. 2), where the gap is established at least in part by thedielectric structure 1350. As shown, the dielectric structure 1350 isarranged so that it is present across the entire area of overlap of thecoils 1312, 1332 and 1313, 1333. According to a further embodiment, andas mentioned above, the dielectric structure 1350 may have dimensionssuch that the dielectric structure 1350 extends beyond some or all ofthe edges of the inductive coupling substrate 1330. In anotherembodiment, the dielectric structure 1350 may have dimensions such thatthe dielectric structure 1350 does not extend beyond, but is retreatedfrom, some or all of the edges of the inductive coupling substrate 1330.

The embodiments depicted in FIGS. 12 and 13 provide for two, one-waycommunication paths. More specifically, referring first to FIG. 12, afirst one-way communication path may be established from left to rightin FIG. 12, or more specifically from bond pads 1216 through transmittercircuitry 1214, coils 1212, 1232, 1234, 1222, receiver circuitry 1224,and bond pads 1226. In addition, a second one-way communication path maybe established from right to left in FIG. 12, or more specifically frombond pads 1226, transmitter circuitry 1225, coils 1227, 1237, 1233,1213, receiver circuitry 1215, and bond pads 1216. Referring now to FIG.13, a first one-way communication path may be established from left toright in FIG. 13, or more specifically from bond pads 1316 throughtransmitter circuitry 1314, coils 1312, 1332, contacts 1334, 1322,receiver circuitry 1324, and bond pads 1326. In addition, a secondone-way communication path may be established from right to left in FIG.13, or more specifically from bond pads 1326, transmitter circuitry1325, contacts 1327, 1337, coils 1333, 1313, receiver circuitry 1315,and bond pads 1316. With the first and second communication paths beingin opposite directions, the embodiments of FIGS. 12 and 13 each mayessentially function as a transceiver.

The embodiments of inductive communication devices 1000, 1100 of FIGS.10, 11 provide for a single communication path through the entireinductive communication device 1000, 1100. Conversely, the embodimentsof inductive communication devices 1200, 1300 of FIGS. 12, 13 providefor multiple parallel communication paths within an inductivecommunication device 1200, 1300. In various embodiments, the inductivecommunication devices 1200, 1300 of FIGS. 12 and 13 may support one-wayparallel communication paths (in the same direction or in oppositedirections) or bi-directional parallel communication paths depending onwhether each instance of the communication circuitry 1214, 1215, 1224,1225, 1314, 1315, 1324, 1325 is designed to be transmitter circuitry,receiver circuitry, or transceiver circuitry. Alternate embodiments ofinductive communication devices (e.g., inductive communication devices1400, 1500) may include a single communication path in which the inputsignal is split, within the device, into multiple paths for inductivecommunication, and then recombined into a single signal after inductivecommunication.

For example, FIG. 14 is a top view of a portion of an inductivecommunication device 1400 with a single communications path in which theinput signal is split, within the device, into multiple paths forinductive communication, and then recombined into a single signal afterinductive communication, according to yet another example embodiment.Similar to the embodiments depicted in FIGS. 10-13, FIG. 14 illustratesthe top surface of a first IC die 1410 (partially obscured), a second ICdie 1420 (partially obscured), and an inductive coupling substrate 1430(overlying and partially obscuring the first and second IC die 1410,1420). A dielectric structure 1450 with a perimeter that extends beyondthe perimeter of the inductive coupling substrate 1430 is positioned ina gap (e.g., gap 180, FIG. 1) between the bottom surface of theinductive coupling substrate 1430 and the first and second IC die 1410,1420.

The first IC die 1410 includes first and second, spatially-separatedcoils 1412, 1413 proximate to the top surface of the first IC die 1410,communication circuitry 1414 (e.g., transmitter, receiver or transceivercircuitry), and a plurality of first bond pads 1416. The second IC die1420 includes third and fourth, spatially-separated coils 1422, 1425,communication circuitry 1424 (e.g., receiver, transmitter or transceivercircuitry), and a second plurality of bond pads 1426. Some of first andsecond bond pads 1416, 1426 may be used to receive voltage supplies(e.g., power and ground), and other ones of first and second bond pads1416, 1426 may be used to receive input signals, convey output signals,receive control signals, or to convey other types of signals. Althougheach set of first and second bond pads 1416, 1426 is shown to includefour bond pads 1416, 1416, each IC 1410, 1420 may include more or fewerbond pads.

Also depicted in FIG. 14 is the top surface of inductive couplingsubstrate 1430 overlying and partially obscuring the first and second ICdie 1410, 1420. The inductive coupling substrate 1430 includes twospatially-separated pairs of serially-connected coils, or morespecifically serially connected coils 1432, 1434 and serially-connectedcoils 1433, 1435. The ends of each pair of serially-connected coils areelectrically coupled together with conductive structures 1438, 1439.

Also depicted in FIG. 14 is dielectric structure 1450, which also ispartially obscured by inductive coupling substrate 1430. When arrangedto provide inductive communication between coils 1412, 1432, 1413, 1433of the first IC die 1410 and the inductive coupling substrate 1430, andfurther inductive communication between coils 1422, 1434, 1425, 1435 ofthe second IC die 1420 and the inductive coupling substrate 1430, thesurfaces of the first and second IC die 1410, 1420 to which the coils1412, 1413, 1422, 1425 are proximate are oriented to face the surface ofinductive coupling substrate 1430 to which coils 1432, 1433, 1434, 1435are proximate. In addition, coils 1412, 1432 are substantially alignedwith each other, coils 1413, 1433 are substantially aligned with eachother, coils 1422, 1434 are substantially aligned with each other, andcoils 1425, 1435 are substantially aligned with each other across a gap(e.g., gap 180, FIG. 1), where the gap is established at least in partby the dielectric structure 1450. As shown, the dielectric structure1450 is arranged so that it is present across the entire area of overlapof the coils 1412, 1432, coils 1422, 1434, coils 1413, 1433, and coils1425, 1435. According to a further embodiment, and as mentioned above,the dielectric structure 1450 may have dimensions such that thedielectric structure 1450 extends beyond some or all of the edges of theinductive coupling substrate 1430. In another embodiment, the dielectricstructure 1450 may have dimensions such that the dielectric structure1450 does not extend beyond, but is retreated from, some or all of theedges of the inductive coupling substrate 1430.

FIG. 15 is a top view of a portion of an inductive communication device1500 with a single communications path in which the input signal issplit, within the device, into multiple paths for inductivecommunication, and then recombined into a single signal after inductivecommunication, according to yet another example embodiment. Similar tothe embodiments depicted in FIGS. 10-14, FIG. 15 illustrates the topsurface of a first IC die 1510 (partially obscured), a second IC die1520 (partially obscured), and an inductive coupling substrate 1530(overlying and partially obscuring the first and second IC die 1510,1520). A dielectric structure 1550 with a perimeter that extends beyondthe perimeter of the inductive coupling substrate 1530 is positioned ina gap (e.g., gap 280, FIG. 2) between the bottom surface of theinductive coupling substrate 1530 and at least the first IC die 1510.The inductive communication device 1500 of FIG. 15 is similar to theinductive communication device 1400 of FIG. 14, except that theinductive coupling substrate 1530 has a pair of spatially-separatedcoils 1532, 1533 for inductively communicating with the first IC die1510, and contacts 1534, 1535 for communicating with the second IC die1520.

The first IC die 1510 includes first and second, spatially-separatedcoils 1512, 1513 proximate to the top surface of the first IC die 1510,communication circuitry 1514 (e.g., transmitter, receiver or transceivercircuitry), and a plurality of first bond pads 1516. Second IC die 1520does not include coils, but instead includes two sets of contacts 1522,1525 proximate to the top surface of the second IC die 1520,communication circuitry 1524 (e.g., receiver, transmitter or transceivercircuitry), and a plurality of second bond pads 1526 proximate to thetop surface of the second IC die 1520. The contacts 1522, 1525 areelectrically coupled with corresponding sets of contacts 1534, 1535 ofthe inductive coupling substrate 1530 to provide for direct electricalcommunication between the second IC die 1520 and the inductive couplingsubstrate 1530. Some of first and second bond pads 1516, 1526 may beused to receive voltage supplies (e.g., power and ground), and otherones of first and second bond pads 1516, 1526 may be used to receiveinput signals, convey output signals, receive control signals, or toconvey other types of signals. Although each set of bond pads 1516, 1526is shown to include four bond pads 1516, 1526, each IC 1510, 1520 mayinclude more or fewer bond pads.

Also depicted in FIG. 15 is the top surface of inductive couplingsubstrate 1530 overlying and partially obscuring the first and second ICdie 1510, 1520. The inductive coupling substrate 1530 includes a pair ofspatially-separated coils 1532, 1533 (which are substantially alignedwith and overlie coils 1512, 1513), and two sets of contacts 1534, 1535.The ends of each of the coils 1532, 1533 are electrically coupled withone of the sets of contacts 1534, 1535 with conductive structures 1538,1539.

Also depicted in FIG. 15 is dielectric structure 1550, which also ispartially obscured by inductive coupling substrate 1530. When arrangedto provide inductive communication between coils 1512, 1532, 1513, 1533of the first IC die 1510 and the inductive coupling substrate 1530, thesurface of at least the first IC die 1510 to which the coils 1512, 1513are proximate is oriented to face the surface of inductive couplingsubstrate 1530 to which coils 1532, 1533 are proximate. In addition,coils 1512, 1532 are substantially aligned with each other, and coils1513, 1533 are substantially aligned with each other across a gap (e.g.,gap 280, FIG. 2), where the gap is established at least in part by thedielectric structure 1550. As shown, the dielectric structure 1550 isarranged so that it is present across the entire area of overlap of thecoils 1512, 1532 and 1513, 1533. According to a further embodiment, andas mentioned above, the dielectric structure 1550 may have dimensionssuch that the dielectric structure 1550 extends beyond some or all ofthe edges of the inductive coupling substrate 1530. In anotherembodiment, the dielectric structure 1550 may have dimensions such thatthe dielectric structure 1550 does not extend beyond, but is retreatedfrom, some or all of the edges of the inductive coupling substrate 1530.

The embodiments depicted in FIGS. 14 and 15 provide for a single one-wayor bi-directional communication path in which an input signal is split,within the device, into multiple paths for inductive communication, andthen recombined into a single signal after inductive communication. Morespecifically, referring first to FIG. 14, when communication circuitry1414 includes either transmitter or transceiver circuitry andcommunication circuitry 1424 includes either receiver or transceivercircuitry, a communication path may be established from left to right inFIG. 14, or more specifically from bond pads 1416 through communicationcircuitry 1414, which divides the input signal into multiple parallelpaths. One instance of the divided signal is then communicated throughcoils 1412, 1432, 1434, 1422, and the other instance of the dividedsignal is communicated through coils 1413, 1433, 1435, 1425. Receiver ortransceiver circuitry 1424 receives and combines the inductivelycommunicated signals, and provides the combined signal to bond pads1426. When communication circuitry 1424 includes either transmitter ortransceiver circuitry and communication circuitry 1414 includes eitherreceiver or transceiver circuitry, a similar communication path may beestablished from right to left in FIG. 14.

Referring now to FIG. 15, when communication circuitry 1514 includeseither transmitter or transceiver circuitry and communication circuitry1524 includes either receiver or transceiver circuitry, a communicationpath may be established from left to right in FIG. 15, or morespecifically from bond pads 1516 through communication circuitry 1514,which divides the input signal into multiple parallel paths. Oneinstance of the divided signal is then communicated through coils 1512,1532 and contacts 1534, 1522, and the other instance of the dividedsignal is communicated through coils 1513, 1533 and contacts 1535, 1525.Receiver or transceiver circuitry 1524 receives and combines theinductively communicated signals, and provides the combined signal tobond pads 1526. When communication circuitry 1524 includes eithertransmitter or transceiver circuitry and communication circuitry 1514includes either receiver or transceiver circuitry, a similarcommunication path may be established from right to left in FIG. 15.

Each of the example embodiments illustrated in FIGS. 10-15 depict one ortwo communication paths, where each communication path provides forinductive communication using one or more primary/secondary coil pairs.Other embodiments may include more than two one-way communication pathsin a particular direction (e.g., one IC die may include multipleinstantiations of transmitter circuitry and corresponding primary coilsand the other IC die may include the same number of instantiations ofsecondary coils and corresponding receiver circuitry). Still otherembodiments may include more than two one-way communication paths inboth directions (e.g., each IC die may include multiple instantiationsof both transmitter and receiver circuitry and corresponding primary andsecondary coils). Still other embodiments may include more than twobi-directional communication paths (e.g., each IC die may includemultiple instantiations of transceiver circuitry and correspondingprimary and secondary coils). Such embodiments are encompassed withinthe scope of the inventive subject matter.

In addition, in FIGS. 10-15, each coil is depicted as four concentric,hexagonal conductive rings. In other embodiments, the conductive ringscomprising a coil may have different shapes, and/or different numbers ofconcentric rings. In addition, as discussed previously, each coil may beformed using concentric rings within multiple conductive layers (e.g.,as depicted in FIGS. 6, 7, and 9). In other embodiments, each coil maybe formed using concentric rings within a different number of conductivelayers from the illustrated and described embodiments.

In the embodiments depicted in FIGS. 3-15, various relative orientationsof coils, communication circuitry, and bond pads are conveyed. Moreparticularly, in each of the embodiments depicted in FIGS. 3-15, thecoils, communication circuitry, and bond pads are shown to be positionedin spatially separated portions of the respective IC die or inductivecoupling substrates. It should be understood that, in alternateembodiments, the communication circuitry and bond pads of an IC die maybe positioned in any suitable position with respect to the coil(s) ofthat IC die. For example, but not by way of limitation, all or portionsof the communication circuitry and/or bond pads may be placed belowand/or in the center of a coil in an IC die. Any suitable relativeorientation of coils, communication circuitry, and bond pads is intendedto be included within the scope of the inventive subject matter.

FIG. 16 is a flowchart of a method for manufacturing IC die (e.g., ICdie 140, 150, 240, 250, 310, 320, 410, 420, 510, 520, 600, 800, 1010,1020, 1110, 1120, 1310, 1320, 1410, 1420, 1510, 1520), inductivecoupling substrates (e.g., inductive coupling substrates 160, 260, 330,430, 530, 700, 900, 1030, 1130, 1230, 1430, 1530) and correspondinginductive communication devices (e.g., devices 300, 400, 500, 1000,1100, 1200, 1300, 1400, 1500), according to various example embodiments.

The method may begin, in blocks 1602 and 1604, by forming first andsecond IC die (e.g., IC die 140, 150, 240, 250, 310, 320, 410, 420, 510,520, 600, 800, 1010, 1020, 1110, 1120, 1310, 1320, 1410, 1420, 1510,1520) for inclusion in the inductive communication device. For example,formation of the first IC die (block 1602) may include forming variouscomponents associated with one or more instantiations of transmitter,receiver, and/or transceiver circuitry (e.g., communication circuitry630, FIG. 6) within an integrated circuit substrate (e.g., substrate602, FIG. 6). In addition, a build-up structure (e.g., structure 610,FIG. 6) may be formed on a top surface of the semiconductor substrate,where the build-up structure includes a plurality of patternedconductive layers (e.g., layers 612-615, FIG. 6) and dielectric layers(e.g., layers 616-620, FIG. 6). During formation of the build-upstructure, the plurality of conductive layers may be patterned to formconductive traces, and conductive vias may be formed through thedielectric layers between conductive layers to provide for electricalcommunication between the layers. In addition, during formation of thebuild-up structure, one or more coils (e.g., coil 640, FIG. 6), each ofwhich includes multiple substantially-concentric conductive rings, maybe formed using one or more of the uppermost conductive layers of thebuild-up structure (e.g., using layers 613-615, FIG. 6). A plurality ofbond pads (e.g., bond pad 650, FIG. 6) may be formed in an uppermostconductive layer to provide for electrical connectivity with thecommunication circuitry.

Formation of the second IC die may be substantially the same asformation of the first IC die in embodiments in which the second IC diealso includes coils for inductively communicating with an inductivecoupling substrate (e.g., the embodiments depicted in FIGS. 1, 3, 4, 10,12, and 14). Alternatively, in embodiments in which the second IC dieincludes contacts for communicating with an inductive coupling substrate(e.g., the embodiments depicted in FIGS. 2, 5, 11, 13, and 15),formation of the second IC die (block 1604) may include forming variouscomponents associated with one or more instantiations of transmitter,receiver, and/or transceiver circuitry (e.g., communication circuitry830, FIG. 8) within an integrated circuit substrate (e.g., substrate802, FIG. 8). In addition, a build-up structure (e.g., structure 810,FIG. 8) may be formed on a top surface of the semiconductor substrate,where the build-up structure includes a plurality of patternedconductive layers (e.g., layers 812, 813, FIG. 8) and dielectric layers(e.g., layers 818-820, FIG. 8). During formation of the build-upstructure, an uppermost conductive layer (e.g., layer 813, FIG. 8) maybe patterned to provide contacts (e.g., contacts 852, 854, FIG. 8) andbond pads (e.g., bond pad 850, FIG. 8), and conductive vias may beformed through the dielectric layers between conductive layers toprovide for electrical communication between the contacts and bond padsand the communication circuitry.

In block 1606, an inductive coupling substrate (e.g., inductive couplingsubstrate 160, 260, 330, 430, 530, 700, 900, 1030, 1130, 1230, 1330,1430, 1530) may be formed. In embodiments in which the inductivecoupling substrate inductively communicates with both the first andsecond IC die (e.g., the embodiments depicted in FIGS. 1, 3, 4, 10, 12,and 14), formation of the inductive coupling substrate may includeforming a build-up structure (e.g., structure 710, FIG. 7) on a topsurface of a substrate (e.g., substrate 702, FIG. 7), where the build-upstructure includes a plurality of patterned conductive layers (e.g.,layers 711-715, FIG. 7) and dielectric layers (e.g., layers 716-720,FIG. 7). During formation of the build-up structure, the plurality ofconductive layers may be patterned to form conductive traces, andconductive vias may be formed through the dielectric layers betweenconductive layers to provide for electrical communication between thelayers. In addition, during formation of the build-up structure,multiple coils (e.g., coils 740, 750, FIG. 7), each of which includesmultiple substantially-concentric conductive rings, may be formed usingone or more of the uppermost conductive layers of the build-up structure(e.g., using layers 713-715, FIG. 7). Electrical connections (e.g.,electrical connections 762, 764, FIG. 7) also may be formed to providefor electrical connectivity between the coils.

Alternatively, in embodiments in which the inductive coupling substratecommunicates inductively with the first IC die and communicates with thesecond IC die over a direct electrical connection with the second IC die(e.g., the embodiments depicted in FIGS. 2, 5, 11, 13, and 15),formation of the inductive coupling substrate may include forming abuild-up structure (e.g., structure 910, FIG. 9) on a top surface of asubstrate (e.g., substrate 902, FIG. 9, where the build-up structureincludes a plurality of patterned conductive layers (e.g., layers911-915, FIG. 9) and dielectric layers (e.g., layers 916-920, FIG. 9).During formation of the build-up structure, one or more coils (e.g.,coil 940, FIG. 9), which includes multiple substantially-concentricconductive rings, may be formed using one or more of the uppermostconductive layers of the build-up structure (e.g., using layers 913-915,FIG. 9). In addition, an uppermost conductive layer (e.g., layer 915,FIG. 9) may be patterned to provide contacts (e.g., contacts 952, 954,FIG. 9). Electrical connections (e.g., electrical connections 962, 964,FIG. 9) also may be formed to provide for electrical connectivitybetween the coil(s) and the contacts.

According to an embodiment, in block 1608, the first and second IC diemay be attached (e.g., using die attach material) to a support substrate(e.g., support substrate 390, 490, 590, FIGS. 3-5). For example, thesupport substrate may form a portion of a leadframe that also includes aplurality of leads (e.g., leads 382, 384, 482, 484, 582, 584, FIGS.3-5).

In block 1610, a dielectric structure (e.g., dielectric structure 170,270, 350, 450, 550, 1050, 1150, 1250, 1350, 1450, 1550) may be placed onor affixed to the first and/or second IC die so that the dielectricstructure substantially covers the portion(s) of the top surface(s) ofthe first and/or second IC die corresponding to the coil(s). Theinductive coupling substrate may then be oriented so that the surface towhich its coil(s) are proximate faces the dielectric structure. Thecoils of the first and/or second IC die and the inductive couplingsubstrate may then be aligned, and the inductive coupling substrate maybe placed on or affixed to the dielectric structure. In embodiments inwhich the inductive coupling substrate and the second IC die areelectrically coupled through corresponding contacts, the correspondingcontacts also may be aligned during the attachment process, and theelectrical connections between the corresponding contacts may be formed.Completion of block 1610 essentially results in the production of one ofthe assemblies of FIGS. 10-15.

In block 1612, the bond pads of the first and second IC die may then bewirebonded to the package leads. In block 1614, packaging of theinductive communication device may then be completed. For example, whenthe inductive communication device is housed within an overmoldedpackage, a mold may be oriented around the leadframe, and non-conductiveencapsulant (e.g., plastic encapsulant) may be dispensed into the moldand cured. Conversely, when the inductive communication device is housedwithin an air-cavity package, a cap may be attached over the top of thedevice to establish an air cavity within which the first and second ICare positioned.

In block 1616, the packaged inductive communication device may then beintegrated into a system in which galvanic isolation between circuits isdesired (e.g., system 100, 200, FIGS. 1, 2). For example, as discussedpreviously, embodiments of inductive communication devices describedherein may be incorporated into a battery charging system for an HEV, aportion of an AC power isolation system, an isolated gate driver, orother types of system in which galvanic isolation between first andsecond circuits is desired.

It should be understood that the various method steps illustrated inFIG. 16 may be performed in orders other than the example orderillustrated, and/or the method may include more, fewer, or differentsteps. In addition, certain steps may be collapsed into a single step,and other single steps may be expanded into multiple steps. In addition,certain ones of the method steps may be performed in parallel, ratherthan serially. Those of skill in the art would understand how to modifythe illustrated flowchart in manners that produce substantially the sameresult. Accordingly, such modifications are intended to be includedwithin the scope of the inventive subject matter.

An embodiment of a device includes first and second IC die, an inductivecoupling substrate, and one or more dielectric components. The first ICdie includes a first coil proximate to a first surface of the first ICdie, and a plurality of first bond pads. The plurality of first bondpads are electrically coupled to the first coil. The inductive couplingsubstrate includes a second coil and a first signal communicationinterface. The second coil is proximate to a first surface of theinductive coupling substrate, and the second coil is electricallycoupled to the first signal communication interface. The second IC dieincludes a second signal communication interface and a plurality ofsecond bond pads. The second signal communication interface iselectrically coupled to the plurality of second bond pads. The first ICdie, the second IC die, and the inductive coupling substrate arearranged within the device so that the first surface of the inductivecoupling substrate faces the first surface of the first IC die and afirst surface of the second IC die, the first coil and the second coilare aligned with each other across a gap between the first IC die andthe inductive coupling substrate, the first IC die and the inductivecoupling substrate are galvanically isolated from each other, and thefirst signal communication interface and the second signal communicationinterface are communicably coupled. The dielectric component(s) withinthe gap are positioned directly between the first coil and the secondcoil.

An embodiment of an inductive communication method includes the step ofproviding a first signal to a first coil of a first IC die, where thefirst coil is proximate to a first surface of the first IC die, and thefirst coil converts the first signal into a time-varying magnetic fieldaround the first coil. The method further includes receiving a secondsignal by a second coil of an inductive coupling substrate as a resultof the time-varying magnetic field coupling with the second coil, wherethe second coil is proximate to a first surface of the inductivecoupling substrate, and the second coil is electrically coupled to afirst signal communication interface of the inductive couplingsubstrate. The method further includes communicating the second signalto a second signal communication interface of a second IC die. The firstIC die, the inductive coupling substrate, and the second IC die arearranged within an integrated circuit package so that the first surfaceof the first IC die faces the first surface of the inductive couplingsubstrate, the first surface of the inductive coupling substrate faces afirst surface of the second IC die, and the first coil and the secondcoil are aligned with each other across a gap between the first IC dieand the inductive coupling substrate so that the first IC die and theinductive coupling substrate are galvanically isolated from each other.

A method of manufacturing an inductive communication device includes thestep of coupling together a first IC die, an inductive couplingsubstrate, a second IC die, and one or more dielectric structures. Thefirst IC die includes a first semiconductor substrate, a first coilproximate to a first surface of the first IC die, and a plurality offirst bond pads. The plurality of first bond pads are electricallycoupled to the first coil. The inductive coupling substrate includes asecond coil and a first signal communication interface. The second coilis proximate to a first surface of the inductive coupling substrate, andthe second coil is electrically coupled to the first signalcommunication interface. The second IC die includes a secondsemiconductor substrate, a second signal communication interface, and aplurality of second bond pads electrically coupled to the second signalcommunication interface. The first IC die, the inductive couplingsubstrate, and the second IC die are arranged within the device so thatthe first surface of the first IC die faces the first surface of theinductive coupling substrate, the first surface of the inductivecoupling substrate faces a first surface of the second IC die, and thefirst coil and the second coil are aligned with each other across a gapbetween the first IC die and the and the inductive coupling substrate.The first IC die and the inductive coupling substrate are galvanicallyisolated from each other. The dielectric structure is positioned withinthe gap directly between the first coil and the second coil. The methodfurther includes the steps of electrically connecting a plurality offirst bond pads of the first IC die to first package leads, andelectrically connecting a plurality of second bond pads of the second ICdie to second package leads. According to further embodiments, formingthe first IC die may also include forming first communication circuitrybetween the plurality of first bond pads and the first coil, and formingthe second IC die may also include forming second communicationcircuitry between the plurality of second bond pads and the secondsignal communication interface.

While the principles of the inventive subject matter have been describedabove in connection with specific systems, apparatus, and methods, it isto be clearly understood that this description is made only by way ofexample and not as a limitation on the scope of the inventive subjectmatter. The various functions or processing blocks discussed herein andillustrated in the Figures may be implemented in hardware, firmware,software or any combination thereof. Further, the phraseology orterminology employed herein is for the purpose of description and not oflimitation.

The foregoing description of specific embodiments reveals the generalnature of the inventive subject matter sufficiently that others can, byapplying current knowledge, readily modify and/or adapt it for variousapplications without departing from the general concept. Therefore, suchadaptations and modifications are within the meaning and range ofequivalents of the disclosed embodiments. The inventive subject matterembraces all such alternatives, modifications, equivalents, andvariations as fall within the spirit and broad scope of the appendedclaims.

What is claimed is:
 1. A method of manufacturing an inductivecommunication device, the method comprising the steps of: couplingtogether a first integrated circuit (IC) die, an inductive couplingsubstrate, a second IC die, and one or more dielectric structures,wherein the first IC die includes a first semiconductor substrate, afirst coil proximate to a first surface of the first IC die, and aplurality of first bond pads, wherein the plurality of first bond padsare electrically coupled to the first coil, the inductive couplingsubstrate includes a second coil and a first signal communicationinterface, wherein the second coil is proximate to a first surface ofthe inductive coupling substrate, and the second coil is electricallycoupled to the first signal communication interface, the second IC dieincludes a second semiconductor substrate, a second signal communicationinterface, and a plurality of second bond pads electrically coupled tothe second signal communication interface, the first IC die, theinductive coupling substrate, and the second IC die are arranged withinthe device so that the first surface of the first IC die faces the firstsurface of the inductive coupling substrate, the first surface of theinductive coupling substrate faces a first surface of the second IC die,and the first coil and the second coil are aligned with each otheracross a gap between the first IC die and the and the inductive couplingsubstrate, the first IC die and the inductive coupling substrate aregalvanically isolated from each other, and the one or more dielectricstructures are positioned within the gap directly between the first coiland the second coil.
 2. The method of claim 1, further comprising:electrically connecting the plurality of first bond pads of the first ICdie to first package leads; and electrically connecting the plurality ofsecond bond pads of the second IC die to second package leads.
 3. Themethod of claim 2, wherein: electrically connecting the plurality offirst bond pads of the first IC die to first package leads includeselectrically connecting first wirebonds between the plurality of firstbond pads and the first package leads; and electrically connecting theplurality of second bond pads of the second IC die to second packageleads includes electrically connecting second wirebonds between theplurality of second bond pads and the second package leads.
 4. Themethod of claim 2, further comprising: coupling a second surface of thefirst IC die to a support structure; and coupling a second surface ofthe second IC die to the support structure, wherein the supportstructure and the first and second package leads form portions of aleadframe.
 5. The method of claim 1, further comprising: forming thefirst IC die by forming, over the first semiconductor substrate, aplurality of first patterned conductive layers, wherein the first coilis formed from multiple substantially-concentric first conductive ringsof the first patterned conductive layers and first conductive viasbetween the first patterned conductive layers; and forming the inductivecoupling substrate die by forming a plurality of second patternedconductive layers, wherein the second coil is formed from multiplesubstantially-concentric second conductive rings of the second patternedconductive layers and second conductive vias between the secondpatterned conductive layers.
 6. The method of claim 1, wherein: thefirst signal communication interface of the inductive coupling substratecomprises a third coil proximate to the first surface of the inductivecoupling substrate and spatially separated from the second coil; thesecond signal communication interface of the second IC die comprises afourth coil proximate to the first surface of the second IC die; thethird coil and the fourth coil are aligned with each other across a gapbetween the second IC die and the inductive coupling substrate; thesecond IC die and the inductive coupling substrate are galvanicallyisolated from each other; and the dielectric structure also ispositioned directly between the third coil and the fourth coil.
 7. Themethod of claim 6, wherein: the third coil is formed from a plurality ofthird patterned conductors in a plurality of third metal layers that areseparated by one or more third dielectric layers; and the fourth coil isformed from a plurality of fourth patterned conductors in a plurality offourth metal layers that are separated by one or more fourth dielectriclayers.
 8. The method of claim 1, wherein: the first signalcommunication interface of the inductive coupling substrate comprises afirst electrical contact proximate to the first surface of the inductivecoupling substrate and spatially separated from the second coil; thesecond signal communication interface of the second IC die comprises asecond electrical contact proximate to the first surface of the secondIC die; and the method further comprises forming an electricalconnection between the first and second electrical contacts.
 9. Themethod of claim 1, further comprising: forming the first IC die byforming first communication circuitry between the plurality of firstbond pads and the first coil; and forming the second IC die by formingsecond communication circuitry between the plurality of second bond padsand the second signal communication interface.
 10. The method of claim1, further comprising: forming the first IC die to include firstcommunication circuitry coupled to the first coil, wherein the firstcommunication circuitry is selected from transmitter circuitry, receivercircuitry, and transceiver circuitry; and forming the second IC die toinclude second communication circuitry coupled to the second signalcommunication interface, wherein the second communication circuitry isselected from transmitter circuitry, receiver circuitry, and transceivercircuitry.
 11. The method of claim 1, wherein the one or more dielectricstructures include one or more of: a material selected from polyimide,polytetrafluorethylene, and benzocyclobutene; a portion of a dielectriclayer overlying the first coil; a portion of a dielectric layeroverlying the second coil; and an air gap.
 12. The method of claim 1,wherein the one or more dielectric structures includes a dielectricmaterial with a thickness in a range of about 25 micrometers to about400 micrometers.
 13. The method of claim 1, wherein the one or moredielectric structures include a dielectric structure having a firstsurface and an opposing second surface, wherein the first surface of thedielectric structure is coupled to the first surface of the first ICdie, the second surface of the dielectric structure is coupled to thefirst surface of the inductive coupling substrate, and the dielectricstructure extends beyond edges of the inductive coupling substrate. 14.The method of claim 1, wherein: the first IC die further includes one ormore additional first coils proximate to the first surface of the firstIC die; the inductive coupling substrate further includes one or moreadditional second coils proximate to the first surface of the inductivecoupling substrate, and one or more additional first signalcommunication interfaces electrically coupled to the additional secondcoils, wherein each of the additional first coils is aligned with acorresponding one of the additional second coils across the gap; thesecond IC die further includes one or more additional second signalcommunication interfaces electrically coupled to the plurality of secondbond pads; and the one or more dielectric structures are positionedwithin the gap directly between aligned pairs of the additional firstcoils and the additional second coils.
 15. The method of claim 1,further comprising: packaging the first IC die, the inductive couplingsubstrate, the second IC die, and the one or more dielectric structurestogether in an air-cavity package.
 16. The method of claim 1, furthercomprising: packaging the first IC die, the inductive couplingsubstrate, the second IC die, and the one or more dielectric structurestogether in an overmolded package.
 17. An inductive communication methodcomprising the steps of: providing a first signal to a first coil of afirst integrated circuit (IC) die, wherein the first coil is proximateto a first surface of the first IC die, and the first coil converts thefirst signal into a time-varying magnetic field around the first coil;receiving a second signal by a second coil of an inductive couplingsubstrate as a result of the time-varying magnetic field coupling withthe second coil, wherein the second coil is proximate to a first surfaceof the inductive coupling substrate, and the second coil is electricallycoupled to a first signal communication interface of the inductivecoupling substrate; and communicating the second signal to a secondsignal communication interface of a second IC die, wherein the first ICdie, the inductive coupling substrate, and the second IC die arearranged within an integrated circuit package so that the first surfaceof the first IC die faces the first surface of the inductive couplingsubstrate, the first surface of the inductive coupling substrate faces afirst surface of the second IC die, and the first coil and the secondcoil are aligned with each other across a gap between the first IC dieand the inductive coupling substrate so that the first IC die and theinductive coupling substrate are galvanically isolated from each other.18. The method of claim 17, further comprising: receiving an inputsignal at a bond pad of the first IC die; converting the input signal tothe first signal by transmitter circuitry of the first IC die; receivingthe second signal by receiver circuitry of the second IC die; producing,by the receiver circuitry, a reconstructed version of the input signalfrom the second signal; and providing the reconstructed version of theinput signal to a second bond pad of the second IC die.